Upon use, pressing an attack direction will cause a swipe attack with high knockback and 3 damage.
The swipe scales in size with Tainted Cain's size.
The swipe will appear further from Tainted Cain the higher his range is.
The swipe can be used to open spiked chests and mimic chests without taking damage.
The swipe can be used to block bullets.
Swiping any pickup on the floor will add them to the bag. The bag's contents cannot be dropped. Up to 8 pickups can be stored and if more are collected, the contents shift left and up, deleting the top left slot and adding at the bottom right. Tapping the switch key cycles the bag's contents left and up in a loop, making it possible to choose which pickup to overwrite.
Double pickups like Double Hearts will add two copies to the bag. Blended hearts will add one red heart and one soul heart.
Sticky nickels can't be picked up unless unstuck.
Chests and sacks can't be picked up, but can be opened with a swipe even behind obstacles.
Once 8 pickups are held in the bag, the bag will show a preview what would be crafted by holding down the Use Pill/Card button.
Crafting an activated item while already holding one will turn the old one into pickups like collecting it would.
If a recipe would result in an item that hasn't yet been unlocked, Breakfast will be crafted instead.
Curse of the Blind hides the crafting preview.
There are a total of 25 different types of consumables that can be placed in the bag. The ordering does not matter for the outcome.
Component Types and Qualities
The cumulative quality of the components impacts the quality of the item received. The pickups belonging to each component type and their qualities are listed as below, starting from top left and counting right and down. The item received can be from the Treasure Room (Item Pool) (1× chance), Shop (Item Pool) (2× chance), Boss (Item Pool) (2× chance), or one of the pools listed in the table below. The pools in the table below require at least 1 of the corresponding component. For example, Devil Room recipes require at least 1 Black Heart.
If the recipe chooses an item from Devil, Angel, or Secret Room pools, the total component quality is lowered by 5 before the resulting item quality, and consequently the resulting item, is determined.
There are , or about 10.5 million, combinations of pickups and consumables that can be used in the Bag of Crafting. The item chosen is based on a formula mapping the chosen consumables, item weights, and quality values into a single outcome.
This means, obviously, that there are numerous combinations that all match the same item and listing them all will not be possible.
The average consumable value is 3.78125.
This item was hinted at by Edmund McMillen before Repentance's release, calling it "The Bag" and hoped that players wouldn't figure it out quickly.
The item is unavailable for anyone except Tainted Cain.
Despite this, it can be "unlocked" for all characters by defeating Delirium as Tainted Cain. Since no item pools contain it, however, the bag cannot actually be obtained by anyone else. It is currently unknown if this unlock has any practical effect.
Bag of Crafting can be dropped when Tainted Cain takes damage while holding Butter!. That means other characters can pick it up that way; however, Tainted Cain is unable to pick it up again and is no longer able to obtain items.
Getting the Bag of Crafting as other characters still allows you to craft items. The special UI of the recipe doesn't appear, however. The Bag will be removed if you craft an active item, simply because the Bag is located in the active item slot (top left).
Swinging the Bag of Crafting while holding Evil Eye may create evil eye tears in the direction fired. Upon pressing the fire buttons, these tears will create a swing identical to that of the Bag of Crafting, even removing pickups caught in the swing. Pickups removed this way will NOT be added to the player's bag.