Tainted Lost

Tainted Lost is a character added in The Binding of Isaac: Repentance. It is the alternate version of The Lost. Tainted Lost is unlocked by reaching Home and using the Red Key, Cracked Key, or Soul of Cain to access a special room in one of the walls while playing as the Lost.

Tainted Lost is just like The Lost, but instead of Holy Mantle, it starts with a Holy Card; it also does not start with the Eternal D6. Like the Lost, Tainted Lost has flight and spectral tears, but no health.

It also starts with a 1.3x damage multiplier, giving it higher starting damage and making most damage ups more powerful. Certain items will be automatically rerolled while playing as Tainted Lost, including most defense-oriented items (see Item Exclusion). To offset the lack of Holy Mantle and limited defensive options, all cards that spawn have roughly a 10% chance of being turned into a Holy Card.

Notes

Just as the Holy Mantle effect from the Holy Card negates damage taken in the first place, items such as Birthright, Missing Poster and Soul of Lazarus will revive Tainted Lost after death. This means that items that normally take effect upon taking damage will affect Tainted Lost upon death and revival.
Beating Delirium with The Lost is not required for Tainted Lost to obtain the Holy Card, or for Holy Cards to spawn during the run.
As with The Lost, Devil Room items and Black Market items can be taken for free, but will be presented as a choice. Taking one item as a deal will cause the others in the room to disappear.

Item Exclusion

Tainted Lost has two mechanics that determine what items it can encounter.

Offensive items

The first mechanic makes it so that any items that are not tagged "offensive" cannot be naturally encountered while playing as Tainted Lost. This disallows items that it can't take advantage of, similar to The Lost's Birthright, but it also prevents many powerful defensive items, such as Dead Cat and Holy Mantle, from naturally spawning. These items will be rerolled, and items that are set drops from mini-bosses (ex. Super Pride dropping Dead Cat) will never be dropped.

Disallowed items can only appear by using Spindown Dice, Death Certificate, as set drops from props (ex. Dry Baby from a skull) or Harbringers (ex. Ball of Bandages), or from Soul of Lilith.

Not all items tagged "offensive" are particularly offense-oriented items. Examples of this include Treasure Map and The D6.

This mechanic seemingly does not work correctly in co-op.

Item quality

The second mechanic uses the item quality system. Items with a quality value of 2 or less have a 20% chance of being rerolled when encountered as Tainted Lost. The new item chosen is not guaranteed to have quality over 2.

Excluded Items

The following items cannot be found while playing as Tainted Lost.

Activated Collectibles

Name	ID	Quote	Description	Quality
Blood Rights	5.100.186	Mass enemy damage at a cost	Takes a full heart of health and deals 40 damage to all enemies in the room. Repeated uses in the same room only take half a heart.	0
Book of Revelations	5.100.78	Reusable soul protection	Increases the chance of a Devil Room / Angel Room appearing while held. Upon use, gives one Soul Heart, and replaces the boss of the current floor with a Harbinger if possible.	3
Breath of Life	5.100.326	Invincibility at a cost	Grants a brief moment of invincibility when the charge bar hits zero. Isaac begins taking damage if the item is held any longer. Isaac creates beams of light when touching enemies while invulnerable, and creates a powerful 4-way beam if blocking damage exactly as the invincibility starts.	1
Converter	5.100.296	Convert your soul	Converts two Soul Hearts or Black Hearts into one filled Red Heart Container. Converts one Soul Heart or Black Heart into one filled Red Heart Container.	2 1
Guppy's Paw	5.100.133	Soul converter	Converts one Red Heart Container into three Soul Hearts.	3
How to Jump	5.100.282	It's time you learned how	Isaac jumps in the direction he is currently moving, allowing travel over obstacles and enemies.	1
How to Jump	5.100.282	It's time you learned how	Isaac jumps in the direction he is currently moving, allowing travel over obstacles and enemies.	1
IV Bag	5.100.135	Portable blood bank	Damages Isaac and spawns a random amount of coins, similar to a Blood Donation Machine.	1 2
Kamikaze!	5.100.40	Become the bomb!	Creates an explosion around Isaac, damaging him and nearby enemies as well as destroying obstacles.	0
Prayer Card	5.100.146	Reusable eternity	Gives Isaac an Eternal Heart.	3
Razor Blade	5.100.126	Feel my pain	Damages Isaac for one heart and grants +1.2 damage for the current room. Subsequent uses in the same room only take half a heart.	0
Satanic Bible	5.100.292	Reusable evil... but at what cost?	Grants one Black Heart. Replaces the boss room item on the current floor with a Devil Deal.	4 3
Satanic Bible	5.100.292	Reusable evil... but at what cost?	Grants one Black Heart. Replaces the boss room item on the current floor with a Devil Deal.	4 3
The Jar	5.100.290	Save your life	When at full health, up to 4 extra Red Hearts can be stored in The Jar. Activating drops the stored hearts on the ground.	0
The Nail	5.100.83	Temporary demon form	Gives one Soul Heart. For the current room; +0.7 damage, -0.18 speed, Isaac breaks rocks and deals contact damage. Gives half a Black Heart. For the current room; +2 damage, -0.18 speed, Isaac breaks rocks and deals contact damage.	2
The Poop	5.100.36	Plop!	Spawns a pile of Poop where Isaac is standing and knocks back nearby enemies. It may yield pickups like regular poop.	0
Unicorn Stump	5.100.298	You feel stumped	Gives invulnerability and increased speed for six seconds, but removes the ability to shoot tears.	1
Yum Heart	5.100.45	Reusable regeneration	Restores one full Red Heart.	1
Clicker	5.100.482	Change	Transforms Isaac into another random character and removes the last item collected.	0
Dull Razor	5.100.486	I feel numb...	Hurts Isaac without depleting health, activating any items that trigger upon taking damage.	1 0
Potato Peeler	5.100.487	A pound of flesh	Removes a Heart Container, increases damage and range, and grants a Cube of Meat.	2
Spin to Win	5.100.655	Let it rip!	Gives +0.5 speed and greatly increases the rotation speed and damage of orbitals for 3 seconds. Passively gives Isaac a spinning top orbital that blocks enemy shots and deals contact damage.	1 0
Sumptorium	5.100.713	Blood to blood	Removes half a heart and creates a Clot familiar that mimics Isaac's movements and tear effects. As Tainted Eve, passively converts health into Clots while firing. Activating returns all Clots to health.	3
Yuck Heart	5.100.639	Gross!	Grants Isaac a Rotten Heart.	1

Passive Collectibles

Name	ID	Quote	Description	Quality
<3	5.100.15	HP up	Grants Isaac one Red Heart container and fully restores Isaac's health.	2
1up!	5.100.11	Extra life	Gives Isaac an extra life. Upon death, he will respawn in the previous room with full health, after which 1up! will disappear.	2
A Snack	5.100.346	HP up	Grants one full Red Heart container. Heals 1 additional Red Heart.	1
Anemic	5.100.214	Toxic blood	After Isaac is damaged, a trail of red creep will be left behind him until he leaves the current room. +5 range. +1.5 range.	1
Ankh	5.100.161	Eternal life?	Upon death, Isaac will respawn as ??? in the previous room, with 3 Soul Hearts.	1 0
Ball of Bandages	5.100.207	Gotta lick 'em all!	Creates an orbital familiar. Collecting additional copies gives it the ability to shoot Charm tears, then chase enemies to deal contact damage, then deal even more contact damage.	2 1
Best Bud	5.100.274	Sworn protector	When hit, spawns a quickly orbiting attack fly similar to Forever alone for the current room that deals high damage.	0
Big Fan	5.100.279	Fat protector	Spawns a large, slow-moving orbital familiar that blocks enemy shots and deals 30 damage per second to enemies. Reduces the speed other orbitals rotate at.	2 1
Black Lotus	5.100.226	HP up x3!	Grants one Red Heart Container, one Soul Heart, and one Black Heart.	2
Blood Bag	5.100.119	HP up	Grants one filled Red Heart container, restores 4 Red Hearts, and increases speed by 0.3.	2
Bloody Lust	5.100.157	RAGE!	Increases Isaac's damage whenever he takes damage, up to six times. The bonus resets when entering a new floor.	2
Breakfast	5.100.25	HP up	Grants one full Red Heart container. Heals 1 additional Red Heart.	1
Broken Watch	5.100.337	I think it's broken	Slows all enemies in every fourth newly-discovered room, with a small chance to speed them up instead.	1
Bucket of Lard	5.100.129	HP up	Grants two empty Red Heart containers, heals Isaac for a Half Red Heart, -0.2 speed. Grants two Red Heart containers, -0.2 speed.	1
Cancer	5.100.301	HP up + you feel protected	Adds 3 Soul Hearts. Grants The Wafer effect for the current room after taking damage.	3
Celtic Cross	5.100.162	Blessing of protection	Grants a chance to trigger the Book of Shadows effect upon taking damage, creating a shield that nullifies all types of damage for 7 seconds.	1
Charm of the Vampire	5.100.62	DMG up + kills heal	Heals Isaac for a Half Red Heart for every 13 enemies killed. +0.3 damage.	1 2
Cube of Meat	5.100.73	Gotta meat 'em all!	Creates an orbital familiar. Collecting additional copies gives it the ability to shoot tears, then chase enemies to deal contact damage, then deal even more contact damage.	2 1
Dark Bum	5.100.278	He wants to take your life	Spawns a familiar that follows Isaac around and collects Red Hearts. For every 1½ Red Hearts collected, Dark Bum will give a reward.	3
Dark Bum	5.100.278	He wants to take your life	Spawns a familiar that follows Isaac around and collects Red Hearts. For every 1½ Red Hearts collected, Dark Bum will give a reward.	3
Dead Bird	5.100.117	Protective buddy	After Isaac takes damage, spawns a flying familiar that chases enemies for the current room, dealing ~4 damage per second. If Isaac is at half a heart or less, the familiar will remain active.	0
Dead Cat	5.100.81	9 lives	Sets Isaac's Red Heart Containers to 1, but grants 9 extra lives. After dying, Isaac respawns with 1 Red Heart Container.	3
Dead Dove	5.100.185	Flight + spectral tears	Grants spectral tears and flight.	3
Dessert	5.100.24	HP up	Grants one full Red Heart container. Heals 1 additional Red Heart.	1
Dinner	5.100.23	HP up	Grants one full Red Heart container. Heals 1 additional Red Heart.	1
Dry Baby	5.100.265	Immortal friend	Spawns a familiar that follows Isaac around and blocks enemy projectiles. Upon blocking a shot, it has a chance of triggering The Necronomicon effect.	3
E. Coli	5.100.236	Turdy touch	Enemies that touch Isaac are transformed into Poop.	1 0
Fanny Pack	5.100.204	Filled with goodies	Has a chance to drop a random pickup when Isaac takes damage.	1
Fate	5.100.179	Flight eternal	Grants flight and one Eternal Heart.	3
Gimpy	5.100.225	Sweet suffering	Gives chance of spawning a Soul Heart when taking damage. Enemies have a chance to drop a Half Red Heart after being killed.	2
Gnawed Leaf	5.100.210	Unbreakable	After standing still and not shooting for a short time, Isaac turns invincible until he moves or shoots.	1
Guardian Angel	5.100.112	Extra protection	Spawns an orbital familiar that blocks enemy shots, deals 7 damage per tick on contact, and increases the speed of all orbital familiars.	2 1
Guppy's Collar	5.100.212	Eternal life?	Grants a permanent 50% chance to respawn with 1/2 of a Red Heart after death.	1
Habit	5.100.156	Item martyr	When Isaac is hit, his active item gains 1 room's worth of charge.	2
Halo of Flies	5.100.10	Projectile protection	Spawns two Pretty Flies that block enemy shots and deal contact damage to flies.	2
Halo of Flies	5.100.10	Projectile protection	Spawns two Pretty Flies that block enemy shots and deal contact damage to flies.	2
Holy Grail	5.100.184	Flight + HP up	Grants flight and one Red Heart container. Heals 1 additional Red Heart.	3
Holy Mantle	5.100.313	Holy shield	Grants a shield that negates the first instance of damage taken from a hostile source once per room.	4
Infamy	5.100.242	Blocks damage... sometimes	Gives Isaac a 50% chance to block projectiles coming from any direction.	2
Infestation	5.100.148	Fly revenge	1-3 Blue Flies randomly spawn every time Isaac gets hit. 2-6 Blue Flies randomly spawn every time Isaac gets hit.	0
Infestation	5.100.148	Fly revenge	1-3 Blue Flies randomly spawn every time Isaac gets hit. 2-6 Blue Flies randomly spawn every time Isaac gets hit.	0
Isaac's Heart	5.100.276	Protect it	Isaac himself is now immune to all damage, and a heart familiar follows him. If the heart is hurt, Isaac is hurt. The heart charges up as Isaac shoots, firing 8 blood shots, knocking back enemies, and leaving a puddle of creep when released.	0
Judas' Shadow	5.100.311	Sweet revenge	Upon death, respawns Isaac as Dark Judas with two Black Hearts in the previous room.	3
Lazarus' Rags	5.100.332	Eternal life?	Upon dying, resurrect as Lazarus Risen in the current room with one Red Heart container and Anemic. Upon dying, resurrect as Lazarus Risen in the current room with one less Red Heart container, Anemic, and +0.5 Damage. Transform into Lazarus when reaching the next floor.	1
Leo	5.100.302	Stompy	Isaac can destroy rocks by walking into them.	1
Little C.H.A.D.	5.100.96	Gives kisses	Spawns a familiar who drops a Half Red Heart every 3 rooms.	2
Lord of the Pit	5.100.82	Demon wings	Grants flight and +0.3 speed.	3
Lunch	5.100.22	HP up	Grants one full Red Heart container. Heals 1 additional Red Heart.	1
Maggy's Bow	5.100.312	HP up + you feel healthy	Gives one Red Heart Container and doubles the healing provided by Red Hearts. Also heals 1 Red Heart when obtained.	2
Magic Scab	5.100.253	HP + luck up	Grants one full Red Heart container, +1 luck. Heals 1 additional Red Heart.	2
Magneto	5.100.53	Item snatcher	Pulls pickups towards Isaac.	1
MEAT!	5.100.193	DMG + HP up	Grants one full Red Heart container, +0.3 damage. Heals 1 additional Red Heart	2
Midas' Touch	5.100.202	Golden touch	Enemies that touch Isaac are temporarily petrified and turn to gold. Any enemy killed while in this state will drop Pennies.	2 1
Missing Page 2	5.100.262	Evil up. Your enemies will pay!	Grants one Black Heart. Upon taking damage that reduces Isaac's health to one heart or less, deals damage to all enemies in the room. Increases the damage of Black Hearts and The Necronomicon-like effects by 40.	0
Mitre	5.100.173	Blessing of purity	Grants a chance of converting any Red Heart pickups that spawn into Soul Hearts instead.	3
Old Bandage	5.100.219	HP up	Grants an empty Red Heart container. Adds a chance of dropping a Red Heart after taking damage.	2
Ouija Board	5.100.115	Spectral tears + tears up	Grants spectral tears that travel through obstacles (but not enemies). +0.5 tears.	2
Piggy Bank	5.100.227	My life savings	Gives 3 Pennies on pick-up. Every time Isaac is damaged, he will drop one or two additional pennies.	1
Placenta	5.100.218	Regeneration + HP up	Grants one full Red Heart container, and a chance to regenerate a Half Red Heart of health every minute of gameplay.	2
Punching Bag	5.100.281	Scape goat	Spawns a Mulligan familiar that wanders randomly. Enemies will attack the Mulligan if it's closer.	1
Punching Bag	5.100.281	Scape goat	Spawns a Mulligan familiar that wanders randomly. Enemies will attack the Mulligan if it's closer.	1
Pyromaniac	5.100.223	It hurts so good +5 bombs	+5 bombs. Grants immunity to explosion damage and causes explosions to heal Isaac. Also grants immunity to fire.	4
Raw Liver	5.100.16	HP up	Grants 2 Red Heart containers and completely restores health.	2
Rosary	5.100.72	Tears + faith up	Grants 3 Soul Hearts. Causes The Bible to appear in any item pool. +0.5 tears.	2
Rotten Meat	5.100.26	HP up	Grants one full Red Heart container. Heals 1 additional Red Heart.	1
Sacrificial Dagger	5.100.172	My fate protects me	Spawns a dagger orbital familiar, blocking enemy shots and dealing a high amount of damage to enemies in contact.	2
Samson's Chains	5.100.321	The ol' ball and chain	Attaches a ball and chain to Isaac that pulls behind him that damages enemies, blocks shots, and destroys most Obstacles.	1
Scapular	5.100.142	Pray for a miracle	Once per room, when Isaac is reduced to his last half heart, he is granted one Soul Heart.	2
Sharp Plug	5.100.205	Infinite charge... at a cost	Damages Isaac in exchange for fully recharging Isaac's current activated item.	2
Skatole	5.100.9	Fly love	Flies become harmless or less dangerous depending on the type.	0
Skatole	5.100.9	Fly love	Flies become harmless or less dangerous depending on the type.	0
Smart Fly	5.100.264	Revenge fly	Spawns an orbital familiar that blocks enemy shots. Upon taking damage, the familiar will pursue enemies for the rest of the room, dealing damage.	2 1
Spiderbaby	5.100.211	Spider revenge	Spawns 1-2 Blue Spiders when Isaac takes damage. Spawns 3-5 Blue Spiders when Isaac takes damage.	0
Spirit of the Night	5.100.159	Scary	Grants spectral tears and flight.	3
Stem Cells	5.100.176	HP + shot speed up	Grants one full Red Heart container and +0.16 shot speed. Heals 1 additional Red Heart	1
Stigmata	5.100.138	DMG + HP up	+0.3 damage, grants one full Red Heart container. Heals 1 additional Red Heart.	2
Stop Watch	5.100.232	Let's slow this down a bit...	+0.3 speed. Automatically inflicts slow to all enemies in every room. +0.3 speed. Upon taking damage, inflicts slow to all enemies for the current room. +0.3 speed. Slows all enemies in every room to 80% speed.	4
Super Bandage	5.100.92	+2 hearts	Grants one full Red Heart container and 2 Soul Hearts.	2
Taurus	5.100.299	Speed down + rage is building	-0.3 Speed. Isaac builds speed while in a room with enemies. At max speed, he gains the My Little Unicorn effect for 5 seconds.	1
The Black Bean	5.100.180	Toot on touch	When taking damage, Isaac farts, poisoning enemies in range. When taking damage, Isaac farts five times, poisoning and knocking back nearby enemies and leaving lingering poison clouds.	0
The Body	5.100.334	I feel all	Adds 3 Red Heart Containers.	3
The Ladder	5.100.60	Building bridges	Allows Isaac to walk across gaps one square across by automatically placing a ladder between the two walkable sections.	1
The Relic	5.100.98	Soul generator	Spawns a cross familiar that drops a Soul Heart after clearing enough rooms.	3
The Soul	5.100.335	I am all	Grants two Soul Hearts. Isaac gains a pulsing aura that repels enemies and projectiles.	3
The Virus	5.100.13	Poison touch + speed up	Isaac poisons enemies on contact. -0.1 speed. +0.2 speed. Poisoned enemies have a chance to drop a black heart when killed.	2
The Virus	5.100.13	Poison touch + speed up	Isaac poisons enemies on contact. -0.1 speed. +0.2 speed. Poisoned enemies have a chance to drop a black heart when killed.	2
The Wafer	5.100.108	Damage resistance	Most sources of damage that would cause more than one-half heart of damage are reduced to one-half heart instead.	4
Thunder Thighs	5.100.314	HP up + speed down + you feel stompy	Destroys rocks upon contact with Isaac. Adds one Red Heart container and lowers Speed.	1
Transcendence	5.100.20	We all float down here...	Grants flight.	3 2
Trinity Shield	5.100.243	You feel guarded	Isaac gains a shield that protects him from enemy shots. It aims in the direction Isaac fires from.	2
Virgo	5.100.303	You feel refreshed and protected	Adds a chance to give a shield that nullifies all incoming damage for 10 seconds upon taking damage. Also converts bad pills into good pills.	2
Cambion Conception	5.100.412	Feed them hate	After taking damage a certain amount of times, a permanent demonic familiar spawns.	2 1
Censer	5.100.387	Peace be with you	Spawns a familiar which creates a circular aura that slows down enemies and enemy shots inside.	3 2
Circle of Protection	5.100.423	Protect me from myself	Surrounds Isaac with a large white halo that occasionally deals Isaac's tear damage to enemies inside it, and can convert enemy shots into friendly homing tears.	2
Crack Jacks	5.100.354	HP up. Don't swallow the prize!	Grants one full Red Heart container and drops a random trinket. Heals 1 additional Red Heart.	2
Curse of the Tower	5.100.371	Embrace chaos	Upon taking damage, spawns six Troll Bombs around the room, similar to the effect of XVI - The Tower.	0
Empty Vessel	5.100.409	I reward an empty vessel	Grants two Black Hearts. While Isaac has no red hearts, grants flight and periodically grants an invincibility shield for a few seconds.	2
Farting Baby	5.100.404	He farts!	Spawns a familiar that follows Isaac and blocks enemy shots. If a shot hits Farting Baby, it has a chance to fart, which charms, poisons, or knocks back nearby enemies.	1
Host Hat	5.100.375	Blast resistance	A host familiar that sits on Isaac's head and has a random chance to block enemy shots and retaliate with 3 tears. Grants immunity to explosions.	3
Immaculate Conception	5.100.413	Feed them love	Upon picking up a certain amount of health, spawn a permanent angelic familiar.	1
Milk!	5.100.436	Don't cry over it...	Spawns a glass familiar that follows Isaac. After Isaac takes damage, the milk spills, and he gains -2 tear delay ( +1.0 fire rate) until leaving the room Spawns a glass familiar that follows Isaac. The milk will block projectiles, and upon blocking 10, the milk spills, giving Isaac +1.0 fire rate for the rest of the floor.	1
Milk!	5.100.436	Don't cry over it...	Spawns a glass familiar that follows Isaac. After Isaac takes damage, the milk spills, and he gains -2 tear delay ( +1.0 fire rate) until leaving the room Spawns a glass familiar that follows Isaac. The milk will block projectiles, and upon blocking 10, the milk spills, giving Isaac +1.0 fire rate for the rest of the floor.	1
My Shadow	5.100.433	Me! And my shaaaadow!	Inflicts fear on all enemies in the room upon taking damage and spawns black friendly Chargers that attack enemies. Spawns a shadow familiar that closely follows behind Isaac. It spawns a black friendly Charger whenever an enemy touches it.	2 1
Night Light	5.100.425	Scared of the dark?	A cone of light shines in the direction Isaac is moving that slows enemies and enemy shots.	1
PJs	5.100.428	You feel cozy	Grants 4 Soul Hearts and fully restores Isaac's health.	2
Sworn Protector	5.100.363	Protective friend	Spawns an orbital familiar which does 105 damage per second and attracts and blocks enemy shots. Upon blocking 10 shots in a room, it drops an Eternal Heart.	3 2
Adrenaline	5.100.493	Panic = power	Increases damage based on how many empty Red Heart containers Isaac has.	2 1
Blanket	5.100.535	You feel Safe	Grants one Soul Heart. Upon entering a boss room, grants a shield that blocks one hit, then disappears.	2
Bozo	5.100.513	Party time!	+0.1 flat damage, grants a Soul Heart. Enemies can randomly become briefly charmed or feared. Taking damage has a chance to spawn a Rainbow Poop.	2
Brittle Bones	5.100.549	Everything hurts	Replaces all Red Heart Containers with 6 empty Bone Hearts. Upon losing a Bone Heart, Isaac fires bones in 8 directions and permanently gains a tears up. Upon losing a Bone Heart, Isaac fires bones in 8 directions and permanently gains a fire rate up.	3
Brittle Bones	5.100.549	Everything hurts	Replaces all Red Heart Containers with 6 empty Bone Hearts. Upon losing a Bone Heart, Isaac fires bones in 8 directions and permanently gains a tears up. Upon losing a Bone Heart, Isaac fires bones in 8 directions and permanently gains a fire rate up.	3
Broken Modem	5.100.514	Lag!	Enemies, enemy shots, tears, and pickups will briefly freeze in place at random intervals. The reward from clearing a room will sometimes be duplicated.	3
Cone Head	5.100.457	Hard headed!	Grants a Soul Heart. Gives Isaac a chance to ignore any damage taken.	2
Dad's Ring	5.100.546	Father's blessing	Creates a ring of light around Isaac that petrifies enemies in contact.	3 2
Dark Prince's Crown	5.100.442	Loss is power	When at exactly one Red Heart, +0.75 tears, +1.5 range, and +0.2 shot speed. When at exactly one Red Heart, +2 fire rate, +1.5 range, and +0.2 shot speed.	1
Greed's Gullet	5.100.501	Money = health!	Grants a Red Heart container for every 25 Coins Isaac has.	1
Hallowed Ground	5.100.543	Portable sanctuary	Spawns a white poop familiar, which turns into a White Poop when Isaac is hurt. White poop has an aura that increases tear fire rate and can block enemy shots. The aura also increases damage by 20% and gives homing.	1
Leprosy	5.100.525	You're tearing me apart!	Taking damage grants a body part orbital that blocks shots and deals contact damage, up to a maximum of three. The body parts are destroyed after blocking enough damage.	1 0
Marbles	5.100.538	Choking hazard	Spawns 3 random trinkets. Taking damage has a 5% chance to swallow Isaac's currently held trinket, gaining its effect permanently.	2
Marrow	5.100.541	HP up?	Grants one Bone Heart and spawns three Red Hearts.	1
Metal Plate	5.100.449	It itches...	Grants one Soul Heart. Enemy shots have a chance to be reflected at the shooter as confusing tears.	1
Midnight Snack	5.100.456	HP up	Grants one full Red Heart container. Heals 1 additional Red Heart.	1
Mystery Egg	5.100.539	Sacrificial insemination	Spawns an egg familiar, which hatches a random friendly monster when Isaac is hurt once per room. The power of the monster improves for each consecutive room cleared without taking damage.	1 0
Shard of Glass	5.100.448	Blood and guts!	Upon taking damage, Isaac has a chance to drop a full red heart, gain 5 range, and leave a trail of damaging red creep for the current room. Taking damage causes Isaac to bleed, spraying a volley of blood in the direction he fires. Bleeding will eventually damage him, but it can be stopped by picking up a Red Heart.	1
Slipped Rib	5.100.542	Projectile shield	Spawns a bone familiar that circles around Isaac and reflects enemy shots.	2 1
Varicose Veins	5.100.452	I'm leaking...	Taking damage releases a ring of 10 high damage tears.	1 0
2Spooky	5.100.554	4me	Enemies near Isaac are afflicted with fear.	1
A Pound of Flesh	5.100.672	Blood money	Devil deals now cost Coins, Shop items now cost health, and consumables in shops are free but surrounded by spikes.	1 0
Astral Projection	5.100.677	The true out-of-body experience!	Causes Isaac to turn into a ghost if he gets hit while in an uncleared room, giving him flight and spectral tears and blocking the next hit he takes.	2 1
Belly Jelly	5.100.690	Bounce away!	Causes enemies to bounce off of Isaac, dealing damage to them if they hit an enemy or obstacle. Also gives Isaac the chance to deflect enemy shots.	3
Binge Eater	5.100.664	All you can eat	+1 Red Heart Container and fully heals Isaac. Item pedestals also offer a random food item. Picking up a food item temporarily grants +3.6 damage and permanently boosts 2 stats.	4
Bird Cage	5.100.610	Fat buddy	The first time Isaac takes damage in a room, a familiar leaps on an enemy, dealing damage and releasing a rock wave. For the rest of the room, it chases enemies similar to Dead Bird.	1 0
Blood Oath	5.100.569	Bleed me dry	Stabs Isaac at the beginning of each floor, draining his Red Hearts. Increases damage and speed for the floor based on the amount drained.	1
Bloody Gust	5.100.695	May your rage bring haste	The first 6 times Isaac takes damage on a given floor, he gains Speed and Fire Rate for the rest of the floor, up to a maximum of +1.02 and +3.00, respectively.	2
Bot Fly	5.100.629	Defense drone	Spawns an orbiting fly familiar that fires shielded tears at incoming enemy projectiles.	3
Candy Heart	5.100.671	Power of love	Gives Isaac a permanent stat boost whenever he heals with Red Heart pickups.	1
Cracked Orb	5.100.675	Shards of knowledge	Unlocks doors and reveals a random room on the map when Isaac takes damage.	1
Cube Baby	5.100.652	Kick it!	Spawns an ice cube familiar that slides around when walked into. It slows and deals contact damage, freezing monsters it kills.	1
Cube Baby	5.100.652	Kick it!	Spawns an ice cube familiar that slides around when walked into. It slows and deals contact damage, freezing monsters it kills.	1
Divine Intervention	5.100.568	Double tap shield	Double tapping a fire key creates a shield that pushes away enemies and reflects enemy projectiles and lasers.	2 1
Empty Heart	5.100.676	It multiplies	If Isaac has one red heart or fewer at the beginning of a floor, he gains an empty red heart container.	1
Giant Cell	5.100.658	Micro friends	Causes Isaac to spawn Minisaac familiars when he takes damage, which chase and shoot at nearby enemies.	1
Heartbreak	5.100.694	Eternal sorrow	Grants 3 broken hearts and +0.25 damage for every broken heart Isaac has. Every otherwise fatal hit will add 2 more until Isaac has nothing but broken hearts.	3
Hypercoagulation	5.100.724	Thick blooded	After Isaac takes damage from an enemy or donates health, launches Red Hearts from Isaac that despawn after 1.5 seconds.	2
Inner Child	5.100.688	Let him free	Upon death, Isaac respawns in the current room with half of a Red Heart, a massive size down, and +0.2 Speed.	2
It Hurts	5.100.560	No it doesn't...	Releases a ring of tears and increases fire rate for the current room when Isaac takes damage. Isaac's tears also leave pools of red creep for the rest of the room.	1
It Hurts	5.100.560	No it doesn't...	Releases a ring of tears and increases fire rate for the current room when Isaac takes damage. Isaac's tears also leave pools of red creep for the rest of the room.	1
Lost Soul	5.100.612	Protect him	Creates a ghostly familiar that closely follows behind Isaac. It dies in one hit, but respawns at the start of the next floor. Each time it survives until the next floor, it rewards Isaac with Soul Hearts, Eternal Hearts, or an Item.	2 1
Lost Soul	5.100.612	Protect him	Creates a ghostly familiar that closely follows behind Isaac. It dies in one hit, but respawns at the start of the next floor. Each time it survives until the next floor, it rewards Isaac with Soul Hearts, Eternal Hearts, or an Item.	2 1
Orphan Socks	5.100.571	Speed up + your feet feel stronger	Prevents creep and floor spikes from damaging Isaac. Also gives Isaac +0.3 speed and 2 Soul Hearts.	2
Psy Fly	5.100.581	Flamboyant protector	Spawns a fly orbital familiar that seeks out incoming enemy shots and destroys them.	4
Sanguine Bond	5.100.692	He awaits your offering	Spawns a special set of spikes in the Devil Room. Taking damage from the spikes has a chance to grant a reward.	1
Sanguine Bond	5.100.692	He awaits your offering	Spawns a special set of spikes in the Devil Room. Taking damage from the spikes has a chance to grant a reward.	1
Spirit Shackles	5.100.674	Unfinished business	On death, Isaac's ghost is chained to his dead body and he can continue to fight with 1/2 of a heart, returning to life after 10 seconds. After it activates, it must be recharged by picking up a Soul Heart.	2 1
Supper	5.100.707	HP up	Grants one full Red Heart container. Heals 1 additional Red Heart.	1
The Swarm	5.100.693	Infest	Spawns eight orbital flies, which turn into Blue Flies after they block a shot. Each time a room is cleared, spawns another orbital fly.	2
Tinytoma	5.100.645	Itching for revenge	Gives Isaac a Teratoma orbital that blocks shots, deals contact damage, and splits into smaller versions of itself upon taking damage. The smaller versions break into blue spiders.	1
Vengeful Spirit	5.100.702	Hot blooded	After taking damage, spawns an orbital wisp that lasts for the entire floor, up to a maximum of six. They fire tears but do not block shots.	1

Strategy

With only a single Holy Card for defense, defensive items become just as important as offensive ones, as taking more than a single hit in the entire run may prove fatal. However, because all items not marked as "offensive" will automatically be rerolled, defensive options available are less plentiful.

A good way to secure a powerful run is to visit as many Boss Challenge Rooms as possible. It is possible for the player to use the alternate floors to their advantage by sticking to the second floor of each chapter. By visiting Downpour II / Dross II, the player can also get an extra boss item from the Mirrored World. This strategy comes with the added risk of having to fight more bosses, but provides the potential to snowball the player's stats and make later floors much easier to survive in.
Be careful of any Chests, which could be a Mimic Chest or a Haunted Chest.
Skulls can be a source of finding cards which in turn can be a Holy Card.
Waiting before using the Holy Card until after the Shop has been found in case a Blank Card is available for sale can prove helpful.
Be wary of taking items that automatically attack enemies in case they kill exploding enemies nearby. Items like 120 Volt, Demon Baby and items that spawn blue flies.

Items Interactions

Favored Items

These items provide significant benefits to Tainted Lost.

Ace of Spades: Chance of changing the room drop reward to a card, and a chance of getting a card as additional rewards from certain things, indirectly increasing the chance of getting a Holy Card.
Birthright: Grants an extra life, respawning in the same room and damaging nearby enemies.
- This extra life item is the only one that can be naturally obtained as Tainted Lost, as all others are rerolled.
- Taking a hit and using Birthright counts as taking damage and will affect items accordingly, such as losing Perfection.
- Summoning Birthright with Lemegeton will grant infinite lives until the wisp is destroyed.
Blank Card: Allows a four-charge reuse of the Holy Card.
- 9 Volt and AAA Battery each reduce the charge time required by one bar.
- The Battery allows storing an extra use of Blank Card, useful in case you take a hit multiple times in a short period.
Bone Spurs: Especially useful against enemies that spawn bullets or other enemies on death, as they will often be instantly blocked or damaged/killed, respectively.
Book of Shadows: Very powerful in combination with Panic Button and 4.5 Volt.
Book of the Dead: The Bone orbitals spawned from this item can block projectiles, greatly increasing survivability.
Book of Virtues / Lemegeton: Rings of wisps can block a lot of projectiles.
Booster Pack: Has about a 40% chance of spawning a Holy Card.
Camo Undies: Allows Tainted Lost to be invisible upon entering a room and plan out his first attack.
Clear Rune: Can be used with protective runes like Rune of Algiz or Soul of Bethany. Similarly, Soul of the Lost can be used for a single-use Holy Mantle for the current room.
- Soul of Lazarus also provides a short invincibility streak after reviving.
Clicker: Becoming Tainted Lost by using Clicker allows Tainted Lost to keep all previously collected items. This allows many useful defensive items that Tainted Lost normally can't collect.
Coupon: Allows an extra item to be taken from devil deals.
Cursed Eye: The downside of the item is inconsequential due to Tainted Lost's lack of health.
D1 / D infinity /Dice Bag: Cards duplicated by D1's effect have an increased chance to be Holy Cards.
Damocles: The downside of the item is inconsequential due to Tainted Lost's lack of health.
- The item can still kill Tainted Lost if resurrected by Birthright or any other acquired respawn item.
Dark Arts: Provides a powerful panic button to escape swarms of enemies and/or bullets.
Deck of Cards: Allows more chances for Holy Cards.
Death Certificate: Tainted Lost can now obtain defensive items, as Death Certificate's item generation ignores Tainted Lost's changes to item availability. This is extremely beneficial, as Tainted Lost can now obtain extra lives such as Dead Cat and protective items such as Holy Mantle.
Echo Chamber: The next three consumables used after Holy Card will grant another mantle.
Endless Nameless: Has a 25% chance to spawn another Holy Card when one is used.
Flat File: Retracts almost all spikes and allows free Curse Room entry.
The Gamekid / My Little Unicorn: On-demand invincibility with contact damage.
Glass Cannon: High damage shots that allow the removal of especially dangerous enemies fast. The downside of the item only comes into effect upon the use of a reviving item and not from consuming a Holy Card.
Glitter Bombs: Bombs may drop a Holy Card when exploding.
Glowing Hourglass: Allows recovery of a Holy Card shield.
Guppy's Tail: can increase the amount of Locked Chests found in a run, and thus allows more chances for Holy Cards to appear.
Homing tears: Allows Tainted Lost to safely position himself almost anywhere in a room while still dealing damage.
Little Horn / Euthanasia: can destroy almost all "invulnerable" enemies (e.g. Poky, Stone Grimace) before they can hurt Tainted Lost. However, Ball and Chain are still invulnerable and dangerous.
Lost Contact: Blocks projectiles.
VI - The Lovers?: Can be safely used to generate items with no loss of durability or risk of death.
Mercurius / Door Stop: Most rooms can be checked for a safe plan of attack, or bypassed entirely.
Missing Poster: Allows a one-time revival upon death, respawning Tainted Lost in the previous room.
- Mysterious Paper has a chance to trigger Missing Poster's effect each room.
Panic Button: Could save Tainted Lost from death when combined with suitable active items.
Paschal Candle: Taking a hit and consuming a Holy Mantle effect allows it to stay at maximum level.
Pause: Can be used with a damaging orbital to get lots of damage on bosses for free.
Perfection: +10 luck with no downside. Tainted Lost's lack of health makes losing it during the run less likely as only using a reviving item will consume Perfection. Luck-based tear effects such as Apple!, Tough Love, Holy Light, and Euthanasia benefit greatly from this extra luck, while also making sure Tainted Lost has a steady supply of pickups from room clear rewards.
- Bird's Eye and Ghost Pepper are exceptionally powerful combined with high luck: at 10 luck, every tear has a 50% chance to be accompanied by a powerful flame, that in the case of Bird's Eye, blocks enemy projectiles. This becomes even more potent when both items are held, as all tears will fire one of these two flames at only 7 luck.
Placebo: Protective pills like Power Pill or Feels Like I'm Walking on Sunshine may be helpful.
Pluto: Smaller size makes Tainted Lost harder to hit.
Soul of Lazarus: Acts as a substitute to Holy Card at the cost of losing Perfection.
Spindown Dice: Allows Tainted Lost to obtain items otherwise hard-coded to not spawn for them.
- Some very useful reroll chains for Tainted Lost include:
  - Belly Button to Cone Head
  - Book of Secrets to Blank Card
  - Cricket's Body to Pyromaniac
  - Free Lemonade to Damocles
  - GB Bug to Farting Baby
  - Juicy Sack to Dry Baby
  - Magic Mushroom to 1up!
  - Meat Cleaver to Bot Fly to Death Certificate
  - Restock to Host Hat
  - Strange Attractor to Thunder Thighs to Holy Mantle
  - Tech.5 to Trinity Shield to Infamy
  - Void to D1
  - We Need To Go Deeper! to The Nail to Lord of the Pit to Dead Cat
  - Lost Contact to Guppy's Collar to Spiderbaby to Gnawed Leaf
  - Salvation to Bloody Gust to Heartbreak
Starter Deck: Increases the chances of finding Holy Cards and allows pill-generating items to spawn Holy Cards.
Teleport 2.0 / Golden Broken Remote / Teleporting cards: allows Tainted Lost to leave Curse Rooms safely.
The Stairway: Creates a ladder to an Angel Room shop at the start of every floor, with the shop potentially selling powerful Angel Room Item Pool items and Holy Cards.
Telekinesis: Can be used to block projectiles or enemies.
Tooth and Nail: Timed invincibility allows exiting Curse Rooms safely.
Uranus: Frozen enemies will not be able to spawn hazards (tears, explosives, other enemies) on death. Icicles from frozen enemies can also slow other enemies and potentially cause a chain reaction, freezing a whole group of enemies.
Wooden Cross: A single-use Holy Mantle per floor. Note that it does not break before Holy Card, thus it is wise to save them for when the shield from Wooden Cross is broken.
Genesis: Will remove current Holy Mantle shield on use, but will give another Holy Card.

Disfavored Items

These items provide significant drawbacks to Tainted Lost.

Any explosive tear effect, such as Fire Mind or Ipecac, greatly increases the chance of fatal self-damage. Since Host Hat and Pyromaniac cannot naturally appear as Tainted Lost, there are very few ways to reliably avoid explosive self-damage.
- The same risk also applies for explosive familiars like BBF, Bob's Brain, and Lil Delirium.
- 3 Dollar Bill, Fruit Cake, and Playdough Cookie have a chance to shoot Fire Mind tears.
The Stompy effect makes firing from cover impossible – all but removing a safe method for Tainted Lost to attack non-flying enemies. Additionally, some obstacles have effects that can cause unavoidable damage if accidentally moved over, such as bomb rocks exploding or blood shots from polyps.
Finger!: May destroy TNT accidentally and without warning.
Little Baggy: Holy Cards will no longer spawn.
IBS: The effects of poop caused by damaging enemies are completely random, which can lead to an accidental death or loss of a Holy Card.
- Butt bombs may hurt you if you are not paying attention, gas clouds from stinky poop could explode in a chain back to you if thrown at fires, and farts generate a gas cloud that will explode if you are next to a fire, leading to an untimely death.

Neutral Items

These items can provide both benefits and drawbacks to Tainted Lost.

Although items which provide temporary invincibility such as A Pony and Mars can allow Tainted Lost to negate damage, their effects are difficult to time, and could result in charging into an enemy and being damaged.
Buddy in a Box: The familiar's potential tear effects are the same as Fruit Cake, and as such have a small risk of carrying Fire Mind for a floor.
Dead Sea Scrolls: Can cause items such as Anarchist Cookbook to trigger, potentially causing damage, but may also spawn a Holy Card via Deck of Cards.
Experimental Treatment: Health is not a factor for Tainted Lost, so it may be included as one of the two stats which are reduced. However, it is more likely to be included as a stat increase, which has no effect.
Lemegeton: Can give Tainted Lost very useful items, such as Birthright, allowing him to have infinite lives until the wisp is destroyed, but it can also give run-ending items such as Ipecac. Because Lemegeton's effect is random, this is completely out of the player's control. If a very bad wisp is gained using Lemegeton, it is recommended to destroy it as soon as possible, but be cautious as this could result in taking damage.
Monster Manual / Soul of Lilith: Can spawn useful familiars, including some which Tainted Lost cannot encounter normally, such as Psy Fly or Sworn Protector. However, they can also spawn useless or even detrimental familiars, such as Bob's Brain or Lil Delirium.
Number One: Decreasing maximum range exposes Tainted Lost to danger, but increasing fire rate may make it easier to defeat enemies.
Sulfuric Acid /Terra: Can skip rooms entirely by breaking doors but also prevent firing from cover.
Teleport!: Can teleport Tainted Lost away from a dangerous room or before a fatal mistake is made. However, the player can teleport to a Curse Room (or to a Secret Room whose only opened exit is a Curse Room) which is inescapable without a Holy Card.

Unlockable Items

Kid's Drawing - Defeat Isaac, ???, Satan, and The Lamb as Tainted Lost.

The Fool - Defeat Ultra Greedier as Tainted Lost.

Soul of the Lost - Defeat Hush and Boss Rush as Tainted Lost.

Haunted Chest - Defeat Mega Satan as Tainted Lost.

Ghost Bombs - Defeat Delirium as Tainted Lost.

Crystal Key - Defeat Mother as Tainted Lost.

Sacred Orb - Defeat The Beast as Tainted Lost.

Gallery

Tainted Lost's transition screen portrait.
Tainted Lost's locked character icon, depicting a closet doorway full of cobwebs.

Trivia

While items like A Dollar, Knife Piece 1, and Knife Piece 2 are not considered items that the Tainted Lost can find, they will still appear for him if the conditions for finding them are met.
While Harbingers will still drop Ball of Bandages or Cube of Meat, C.H.A.D. will not drop Little C.H.A.D..
If invincibility is used to play Blood Donation Machines, they can still produce a Blood Bag as a reward.
Inner Child will still spawn in the hidden closet in Home.
The achievement for unlocking Tainted Lost is "The Baleful", a possible title for the character.
- "Baleful" means "ominous" or "harmful or malignant in intent or effect", possibly referring to how Tainted Lost has higher base damage than his regular counterpart and can find better items.
- A more archaic meaning of "Baleful" is "Something/Someone wretched or miserable", and considering how Tainted Lost is incapable of using defensive heavy builds, being constantly at the mercy of enemies and dying usually at two hits, fit with this use of the word.
- "The Baleful" is Tainted Lost's character name in Four Souls.
Before the 1.7.5 update, it was possible for Tainted Lost to find Yuck Heart and Best Bud, despite these items being useless for the character.
- Additionally, Heartbreak could be found and utilized to essentially gain 4 extra lives and extra damage, but was removed from the tag list.
Tainted Lost's unlock drawing could be a reference to a transition nightmare Isaac can have, depicting The Lost talking to Mom from the attic.
Tainted Lost unlocks 0 - The Fool?; the character can be linked to both the numeration and meaning of the Fool.
- The Fool's numeration can be either 0 the lowest trump or 22 the highest trump, linked to his attributes — better items, no mantle, no health — as Tainted Lost will die in a single hit at any point, but can also build the strongest runs of any character because of those same attributes.
- Reverse fool means apathy and nullity; this approach is often recommended to face Tainted Lost's runs because of how demanding the character is and how easy it is to lose these runs despite how powerful the character can become.
- In a literal reversal of "the beginning of the journey" which The Fool represents, Tainted Lost represents the complete end of Isaac's existence, after his own mortal remains has vanished and even his own soul erodes into dust and cobwebs along with the house and material objects that hold his last remnant memories.
Tainted Lost's starting health is listed as "?" on the character selection screen.