Tainted Cain

Tainted Cain is a character added in The Binding of Isaac: Repentance. He is the alternate version of. Tainted Cain is unlocked by reaching and using either the  or the  to access a special room in one of the walls while playing as Cain. He has an identical appearance to Cain with the exception of a giant blood wound behind his left eye patch.

Tainted Cain starts with 2 heart containers, 1 key, and the in the consumable slot.

Tainted Cain can't get items (except story items) through any means other than the Bag of Crafting, and attempting to do so will transform the item into an assortment of consumables. If this is done in a room with a special loot pool, one of the dropped consumables will be guaranteed to be the one which biases crafting recipes towards that pool.

Crafting an active item when already holding one will also transform the old active item into consumables instead of dropping it, following the same above rules.

Item & Strategy Notes

 * Many alternate ways of getting pedestal items, such as Shops or Devil Rooms, become irrelevant or outright detrimental when playing as Tainted Cain. Taking a Devil Deal only has the immediate benefit of dropping Black Hearts, which can be accomplished without spending Heart Containers through replacing Tainted Cain's Active Item while present in the Devil Room. As such, it is often more beneficial to skip the first Devil Room and instead potentially get free materials from a later Angel Room.
 * Shops do, however, have the use of purchasing Cards or Pills, which can then be dropped on the ground and used as ingredients.
 * Cards should be checked for their effects before being put in the bag of crafting, since a few may be more beneficial to use than part of a recipe.
 * It may be beneficial to leave room rewards and pedestal item drops for a later time, then returning to craft items out of the more expensive materials once more are gathered.
 * Players should be careful about crafting range-increasing items, as these will offset the hitbox of the Bag of Crafting's swing. This can, with a high enough range stat, make it very difficult to grab crafting materials precisely.
 * However, keep in mind the base range of the Bag of Crafting's swing is usually enough to get pickups behind rocks.
 * Tainted Cain starting with but not occupying his Activated Item slot makes it very powerful for reaching certain Achievements (because you don't need to depend on random number generation). These achievements include:
 * Achievements that require collecting all items.
 * Achievements that require collecting a certain number of items of a certain category.
 * Tainted Cain's completion marks, which can be achieved by crafting powerful combinations of items, such as (which can be created with the most common items so can usually be crafted in the first floor) and familiars that attack on their own like .  Selective crafting may make it hard to beat the time limits for Boss Rush and, but you can craft the alternate items to unlock those levels, as well as the alternate items to unlock the golden door in The Chest or The Dark Room.  You can also craft these item combos and then switch characters using items like  or  to handle a completion mark that you were finding particularly difficult.
 * It is recommended to unlock all pickups, as items like, and  require (or are difficult to craft without) unlockable pickups.

Good Items
Of course it isn't expected for the player to learn every individual crafting recipe, though it may be beneficial to memorize or have a few noteworthy cheap recipes at the ready.


 * has a relatively cheap recipe of one soul heart and seven pennies. Combined with the fact that Alabaster Box will be crafted fully charged and guarantees at least one soul heart and several Angel room items, it is possible to craft many other powerful items from repeating its recipe.
 * After patch 4.0.3 Alabaster box has no charge when picked up.
 * has some relatively cheap recipes, and is one of the most important items for Tainted Cain, doubling the amount of pickups each pedestal item turns into. Crafting this before  also allows easy access to other character's Birthright effects.
 * Black Lipstick / Daemon's Tail / Bible Tract: Increases the chance of getting black or eternal hearts allowing easier access to stronger items.
 * can give you access to significantly larger amounts of pickups throughout a run if crafted early.
 * combined with and  can be used to generate infinite batteries, which can lead to game-breaking combinations due to it being able to duplicate any pickup infinitely with the D1. Given the relative cheapness of these items, you can craft them as soon as Chapter 1.
 * Likewise,, and two  grants the same effect, with the added bonus of duplicating all pickups instead of only one. Bear in mind, however, that  can't be crafted and must be found.
 * can be crafted from common pickups, and is a great Active Item to hold onto, allowing Tainted Cain to reroll massive amounts of pickups anytime a pedestal item is broken, potentially into chests which can give even more.
 * can be crafted to generate Lucky Pennies for more expensive recipes.
 * allows much more freedom to utilize black hearts and eternal hearts as you see fit, especially when combined with Goat Head or Eucharist.
 * may be useful to generate large amounts of pickups in one room, especially special rooms.
 * can be crafted repeatedly to make any character start with excessive amounts of items. (Stacks up to 10 items).
 * Equality! is a trinket and thus not craftable, but works like a universal toggleable and effectively speeds up all crafting twofold. The loss of precision from getting everything in pairs can be partially offset by shifting your Bag of Crafting inventory in odd steps, so an odd amount of pickups will usually remain after bagging a new pair of pickups.
 * allows Tainted Cain to produce a number of useful pickups for crafting, in particular gold bombs, hearts and keys which are harder to find. Furthermore, the gold bombs and keys allow Tainted Cain greater access to further resources without needing to expend normal bombs and keys.
 * can allow for additional pickup generation, especially if combined with, , or . Of these three, No. 2 is the cheapest to craft and typically the most convenient to utilize in this fashion, though it is also quite slow.
 * has an exceptionally easy crafting recipe, and along with an auto-fire familiar such as or  it can be used for a slow yet guaranteed victory.
 * / are expensive to craft, but can give you consistent access to black hearts and/or eternal hearts, making it easier to craft Devil and/or Angel pool items.
 * is very expensive, but can be used to force entry into Boss Rush and Hush. Due to how slow and methodical Tainted Cain typically is, this item can be incredibly useful for getting completion marks.
 * , while somewhat expensive, can be useful in the long term, as Soul Hearts are a common requirement for recipes.
 * allows you to more easily control what kinds of pickups you get. By putting a pedestal item in the box and placing it back down inside of a special room, you can guarantee the pickup associated with that room. This eliminates the need to constantly be spending resources crafting new active items, but requires a 4-room recharge between uses, making it a tradeoff.
 * Myosotis, while not craftable, can be a good trinket to keep an eye out for, as it allows the transport of 4 pickups to the next floor.
 * will give you a much larger variety of ingredients throughout a run. It should be noted that you cannot put both pickups generated by Options? into the Bag of Crafting. You will only take the closest one to you, and the further pickup will disappear.
 * is arguably the cheapest item that can be crafted, able to be crafted with 8 pennies. Not only can it be used as a way to mill off coins in exchange for other materials and generate a large number of pickups in one room, a second one can easily be crafted on top of the first in any special room to create the pickup that corresponds to its item pool. For example, replacing your active item with a slot machine in a Secret Room will always generate a bone heart.
 * grants healing from explosions, and grants the ability to explode on command.  Throw in  to stop full heart damage, then Isaac can no longer take more damage than he can heal.
 * is a great panic craft, able to be made out of one key, one bomb, and six pennies. If a run is struggling, this can be a good item to extend it.
 * is very cheap to craft, requiring only 4 pennies, 3 keys, and a bone heart. Because you can guarantee this is one of the first items encountered in a run, it can be the backbone of an extremely powerful synergy of only a handful of items, such as Red Stew and Soy Milk.
 * Perfection is a fantastic trinket to pick up after obtaining Rock Bottom, as the massive luck bonus will persist after a hit. The resulting bonus luck will be providing a steady supply of chests which contain plenty of collectibles to use in crafting, among other useful attributes that high luck provides.
 * takes quite a bit of thought to craft, though allows for Tainted Cain to continue a run almost indefinitely if crafted repeatedly, potentially earning every Completion Mark outside of Greed Mode in a single run.
 * can be a useful investment to make, as it allows for the player to carry an Active Item they intend to use, as well as an Active Item to be turned into materials in special rooms.
 * is a very easy way to access Curse Rooms for free, allowing consistent generation of rotten hearts.
 * and can be used as a way to boost Tainted Cain's stats or damage output in rooms with multiple pedestals, due to direct stat up items being a bit hard to come by.

Bad Items

 * ,, and  will require intense micromanagement so they don't take essential materials and mess up your plan. Coins, red hearts and keys will still prove to be useful even in harder recipes.
 * and may sound good for Tainted Cain in theory, but in practice these will make it much harder to craft items precisely. Double pickups will yield 2 of the associated crafting ingredient, which can lead to frustrating situations if a recipe specifically calls for 1 of a particular pickup.
 * ,, and serve no purpose without  due to Tainted Cain being unable to pickup anything they reroll.
 * and are pointless without.
 * Butter! should always be avoided, using bag of crafting will cause Tainted Cain to drop it, preventing him from gaining any more items, unless he has.

Trivia

 * The achievement for unlocking Tainted Cain is "The Hoarder", a possible title for the character.