Isaac mod
Double Holy Cards for Tainted Lost
A Binding of Isaac mod for Tainted Lost, the character that dies to a single hit. Every random card gets twice vanilla's chance to become a Holy Card, the one thing that buys a second life - 20% instead of 10%, measured in game.
Why it exists
Tainted Lost dies to a single hit, and a Holy Card is the only thing that shields that hit. The game already gives the character a bonus roll for it on every card that spawns. This mod gives one more: noticeably more Holy Cards over a run, while the character keeps its edge.
What it changes
Every card the game rolls at random gets the extra chance - room rewards, chests, shop cards (which keep their price) and items that roll cards, such as Deck of Cards. Cards dropped from the inventory come back as they were, scripted cards like The Fool on Depths II stay fixed, and runes, soul stones and objects such as Dice Shard keep vanilla’s odds. Other characters are untouched; the mod acts only when a Tainted Lost is in the game, co-op included.
Where the 10% comes from
The wiki only says “roughly 10%”. The exact value comes from REPENTOGON’s
reimplementation of the game’s card roll, which has to reproduce the original: one
RandomInt(10) == 0 check whenever any player is Tainted Lost. Reaching 20% on top
of that takes an extra roll of 1/9, since 0.1 + 0.9 × 1/9 = 0.2. The roll uses the
RNG the game hands to the callback, so runs stay deterministic per seed.
Measured in game
203 random cards spawned in one Tainted Lost run gave 39 Holy Cards, or 19.2%, against an expected 18.9% once runes and objects are counted in. The 95% confidence interval of 13.8 to 24.6% rules out both vanilla’s 10% and a stacked 28%.
Written in Lua against the vanilla API, so it needs no REPENTOGON. CI checks every
push with lua-language-server against the vanilla API definitions and refuses a
release with debug values left in. Released under the Apache License 2.0.