Tainted Lost

What you start with

The mechanics that actually govern this character.

• No health at all, flight, spectral tears, a x1.30 damage multiplier, 1 coin, and a Holy Card in the pocket slot in place of Holy Mantle. No Eternal D6.
• Any item not tagged offensive is automatically rerolled when encountered. That removes Holy Mantle, Dead Cat and almost all defensive items from natural spawns, and mini-boss set drops such as Super Pride's Dead Cat never drop at all. Some non-obvious items keep the offensive tag, including Treasure Map and The D6.
• Second filter: items of quality 2 or lower have a 20% chance of being rerolled on sight, and the replacement is not guaranteed to be any better.
• To compensate, roughly 10% of all cards that spawn are converted into Holy Cards. This does not require having beaten Delirium as The Lost.

How to play them

• The gimmick in plain language: you get exactly one shield and the game actively refuses to hand you a second one. Every Holy Card is a life, so every card that drops anywhere is a lottery ticket for another life.
• Break every skull and open every sack. Skulls drop cards, and cards are the only defensive resource the exclusion list lets you have.
• Farm Boss Challenge Rooms. On Repentance they require 1 heart or less in TOTAL to enter, which you always satisfy at zero, and they always contain a Boss pool item. Route through the second floor of each chapter deliberately.
• Downpour II or Dross II additionally gives an extra boss item from the Mirrored World. More bosses, more risk, but this is how you snowball stats into being able to survive Chapter 4 onwards.
• Devil Room and Black Market items are free but presented as a choice - taking one despawns the rest. Think before you touch a pedestal.
• Hold the Holy Card until you have seen the Shop, in case there is a Blank Card for sale that would let you reuse it.
• Chests are a real threat: a Mimic Chest or Haunted Chest ends the run. Be equally wary of anything that auto-attacks (120 Volt, Demon Baby, blue flies) killing an exploding enemy next to you.

Items to hunt for

Strong on this character specifically, not just strong.

• Blank Card: turns the Holy Card into a reusable 4-charge shield. 9 Volt and AAA Battery each shave a bar; The Battery banks a second use for back-to-back hits.
• Death Certificate: its item generation ignores the Tainted Lost exclusion list entirely, so it can hand you Holy Mantle, Dead Cat and everything else you are locked out of. Highest-value item in the game for this character.
• Spindown Dice: the other route past the exclusion list. Useful known chains are Strange Attractor to Thunder Thighs to Holy Mantle, We Need To Go Deeper! to The Nail to Lord of the Pit to Dead Cat, Book of Secrets to Blank Card, Free Lemonade to Damocles, and Meat Cleaver to Bot Fly to Death Certificate.
• Birthright: the only extra life that spawns naturally for you, respawning you in the same room and damaging nearby enemies. A Birthright wisp from Lemegeton gives infinite lives until the wisp is destroyed.
• Perfection trinket: +10 luck with almost no downside, since only a revive consumes it and a Holy Mantle break does not. At high luck, Bird's Eye and Ghost Pepper are extremely strong - with both held, every tear fires one of the two flames at only 7 luck, and Bird's Eye flames block enemy shots.
• Physical shot blockers, which is the only real defence available: Book of the Dead's bone orbitals, Book of Virtues and Lemegeton wisp rings, Lost Contact, Telekinesis, Bone Spurs.
• Holy Card generators: Booster Pack (about 40%), Endless Nameless trinket (25% to replace a spent Holy Card), Starter Deck, Deck of Cards, Ace of Spades, D1, D Infinity, Dice Bag, Guppy's Tail, Glitter Bombs, and The Stairway's per-floor Angel Room shop.

Traps to refuse

Picks that are neutral or good elsewhere and bad here.

• Any explosive tear effect: Ipecac, Fire Mind, and the Fire Mind rolls that 3 Dollar Bill, Fruit Cake, Playdough Cookie and Buddy in a Box can produce. Host Hat and Pyromaniac cannot spawn for you, so there is no way to be immune and self-explosions are simply fatal.
• Explosive familiars for the same reason: BBF, Bob's Brain, Lil Delirium.
• Little Baggy: card drops become pill drops, which shuts off Holy Card generation completely. This is the closest thing to a hard brick on the character.
• Stompy and other size-up effects: you can no longer fire over rocks, which removes the safest way to fight ground enemies, and moving over bomb rocks or polyps becomes unavoidable damage. Sulfuric Acid and Terra similarly destroy the cover you were hiding behind.
• IBS and Finger!: both create random effects you did not ask for. IBS poop can throw butt bombs or gas clouds that chain-explode back onto you; Finger! detonates TNT without warning.

Cheese and techniques

Verified against 1.7.9 on console — anything patched, PC-only or Repentance+ only is called out rather than listed.

• Teleport out of Curse Rooms instead of eating a Holy Card: Teleport 2.0, a golden Broken Remote, or any teleport card works. Flat File retracts almost all spikes and gives free Curse Room entry outright. Tooth and Nail's timed invincibility also gets you out.
• Echo Chamber after using the Holy Card: the next three consumables used each grant another Holy Mantle.
• Clear Rune plus a protective rune (Algiz, Soul of Bethany, Soul of the Lost) for extra one-room shields. Soul of Lazarus is a spare life, at the cost of consuming Perfection. The Wooden Cross trinket also gives one Holy Mantle per floor and it always breaks BEFORE your Holy Card, so carry both and treat the card as the reserve.
• Paschal Candle stays at maximum level when a Holy Mantle absorbs the hit, so shielded hits do not reset its stacking.
• Not available on 1.7.9 console: there is no debug console or Repentogon item injection. Death Certificate and Spindown Dice really are the only ways around the exclusion list.

Getting the marks

• 7 secrets. Isaac, ???, Satan and The Lamb collectively unlock Kid's Drawing. Mega Satan gives Haunted Chest, Boss Rush OR Hush gives Soul of the Lost, Greedier gives the 0 - The Fool? card, Delirium gives Ghost Bombs, Mother gives Crystal Key, The Beast gives Sacred Orb.
• Do The Beast early if you can. Sacred Orb stops quality 0-1 items from appearing and rerolls quality 2 items 33% of the time, which raises the floor of every pool for every future run - and it is unusually valuable to Tainted Lost specifically because his quality-2 reroll filter already fights him.
• Godhead is a NON-tainted Lost unlock (all hard marks with The Lost) and is not needed here. You already have it.
• Mom's Heart and normal Greed mode give no secret for tainted characters; both marks still need filling for the note and for Death Certificate.