Tainted Keeper

What you start with

The mechanics that actually govern this character.

• Starts with and is capped at 2 coin hearts, plus 1 bomb. Tears -2.2 and luck -2, and he fires four tears at once like Mutant Spider. Heart pickups all become blue flies; picking up a coin refills a coin heart and does NOT add to your wallet.
• Almost every item must be bought with coins: Treasure Room, Boss Room, Devil Room and Angel Room items all have prices. Anything that would normally cost two hearts in a Devil Deal costs 30 coins, as do the top Angel items (Sacred Heart, Godhead, Holy Mantle, Crown Of Light, Spirit Sword, The Body, Revelation, The Wafer, Trinity Shield and others).
• Every enemy killed drops a coin that vanishes quickly. Champions and mini-bosses drop 2; bosses drop several and their coins linger longer. Enemies spawned mid-fight are not guaranteed to drop.
• Shops are upgraded for him: no key needed, larger stock, and at max level 8 terminals with a guaranteed Shop item, a Boss item and two Treasure Room items. These improved shops do NOT appear in Greed mode.

How to play them

• The gimmick in plain language: money is health, money is progression, and money evaporates in about two seconds. You are doing a smash-and-grab with two hit points and terrible fire rate.
• Because Shops already stock Treasure Room items, skipping the Treasure Room for a Planetarium is usually correct.
• Devil deals beat Angel rooms for him: taking one Devil item does not despawn the others, but taking one Angel item does. Devil's Crown's usual downside is mostly irrelevant since you were paying for the item either way.
• Understand your broken fire-rate curve. At or below -0.77 tears, Tears stat gains barely convert to fire rate: his first four Tears Up pills give roughly 0.07, 0.09, 0.10 and 0.12 fire rate, and the fifth gives 0.52. Direct fire-rate items are worth far more than Tears items until you cross that threshold, after which his quad shot makes Tears items exceptionally good.
• Play deliberately aggressive. Run into a pack, use your invincibility frames, collect the coins the pack drops and heal back up. High speed matters mostly for outrunning the coin despawn timer.
• Curse Rooms: if the room is empty, walk in and immediately walk back out while invincibility frames are active and you keep your second heart. If enemies are there, their coins keep you alive - just do not linger.
• Free items still exist and should be prioritised: mini-boss drops, golden and red chest items, beggar and machine payouts, items spawned by other items, all quest items, and boss drops in The Void.

Items to hunt for

Strong on this character specifically, not just strong.

• Greed's Gullet: up to 4 extra coin hearts, and up to 12 additional containers with Deep Pockets. This is nearly the only real health upgrade available. Careful - dropping below each coin threshold takes the heart back.
• Mother's Kiss trinket: a third coin heart, and it stacks if you swallow multiple copies with Marbles or a Gulp! pill. Losing the trinket loses the heart.
• Birthright: strongly attracts the vanishing coins, which converts directly into more items and more healing. Broken Magnet, Super Magnet and Magneto are weaker versions.
• Penny trinkets across the board, because your coin throughput is enormous: Burnt Penny (bombs), Counterfeit Penny (extra coin per pickup), Charged Penny (active charging, effectively Jumper Cables), Flat Penny (keys), Rotten Penny (blue flies).
• Number One and Odd Mushroom (Thin) are the cleanest fire-rate fixes, taking him from a standing start to 1.55 and 1.82 tears per second respectively.
• Brittle Bones: a one-time fire-rate and tears boost plus 24 blue flies for free, because he has no red heart containers to lose. The bonus is kept even if the item is later removed or rerolled.
• Deep Pockets (1-3 coins on otherwise-empty room clears and a 999 coin cap), Keeper's Sack, Keeper's Box, Head of the Keeper, Money Power, Steam Sale, and Isaac's Heart (invulnerable body with contact damage makes coin collection trivial, and pairs with Midas' Touch).

Traps to refuse

Picks that are neutral or good elsewhere and bad here.

• Mutant Spider and The Inner Eye. They stack badly with his native quad shot: Mutant Spider makes it six tears at x0.42 tears (about 36% less DPS) and The Inner Eye makes it five at x0.51 (about 38% less).
• Heartbreak and the VI - The Lovers? card: they instantly break the second coin heart, leaving you one hit from death, and no HP upgrade can restore it until the broken heart is removed.
• Anything that moves coins: Black Hole, Lodestone and Ocular Rift pull or push coins out of reach, and Butt Penny shoves them away too. Mini Mush and Pluto shrink your hitbox and cost you pickups.
• E. Coli and Flush! - enemies turned into poop drop no coins. Room-wide damage items such as Toxic Shock and Butt Bombs kill everything at once so the coins all time out together.
• Dead weight: Damocles does nothing because every item still has to be bought; HP ups other than Greed's Gullet and Mother's Kiss do nothing; The Wafer, Cancer and Empty Vessel have no effect; Whore of Babylon can never trigger because he cannot have half a coin heart.

Cheese and techniques

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

• Burnt Penny bomb loop: kill most of a room, use Burnt Penny's bombs to blow out through a wall, and re-enter to reset the room. In a dense enough room this is effectively infinite coins and bombs.
• Room re-entry farming: coin drops are decided when the room generates, so a room that dropped a dime or nickel will do so again. Door Stop, Mercurius, Ventricle Razor and Cursed Penny all enable this - but the payout decays each visit and eventually stops entirely, so it is a burst, not a well.
• D7 in a Shop or Secret Room re-fights Greed and Super Greed for large coin dumps, and can be used to reset a room and collect a valuable coin twice. Sack Head contents are seeded the same way.
• Sacrifice Rooms are far more usable for him than for anyone else because enemies reliably restock health as coins. Alternate spike hits with clearing monster rooms. The Angel Room item at the sixth sacrifice still has to be bought; the item at the seventh sacrifice is free.
• Dataminer underflow works on 1.7.9: two tears-down procs put him below zero tears and he fires up to 120 tears per second. He is uniquely close to the threshold because he starts just under 1.00 fire rate. Any tears item taken afterwards re-breaks it, so it is a commit.

Getting the marks

• 7 secrets. Isaac, ???, Satan and The Lamb collectively unlock Keeper's Bargain. Mega Satan gives Golden Penny, Boss Rush OR Hush gives Soul of the Keeper, Greedier gives the XII - The Hanged Man? card, Delirium gives Keeper's Kin, Mother gives Cursed Penny, The Beast gives Strawman.
• Greed and Greedier are harder for him than the main path because the upgraded Tainted Keeper shops do not spawn in Greed mode, so his whole economic advantage disappears. Bank coins hard before Ultra Greedier.
• Boss Rush items must still be bought, and buying one starts the waves - so have coins in hand before you walk in, or you cannot start it at all.
• Mom's Heart and normal Greed give no secret for tainted characters; both marks still have to be filled for the note and for Death Certificate.