Cain is an unlockable character in The Binding of Isaac. He is unlocked by having a total of 55 coins at any one time in a playthrough (not just attaining 55 or more coins in a playthrough).
A quick way to unlock Cain is to go to a slot machine and put coins in around 15 times or so. Most of the time, the machine will explode. This explosion occasionally includes a dollar, which gives you 99 coins automatically. Another quick way to unlock Cain is through the use of the 2 of Diamonds, which will double your coins, letting you easily reach 55 coins.
Cain starts out with 2 hearts, 3 points of attack power, 2 points of attack speed, 1 point of range, and 3 points of speed. He also starts the game with a Key and the Lucky Foot.
Gameplay Tips & Strategy
Cain starts with lower HP than Isaac but with higher speed and damage.
Cain, with his Lucky Foot starter item, makes for the most viable character when looking for better items, more money and more discounts in shops. His strong stat loadout and extra key make him a player-friendly alternative to Isaac.
Cain's lack of an activate item makes him versatile - make do with whatever comes your way!
A good strategy for Cain is to exploit arcades. His Lucky Foot item will help in acquiring more coins which can be used in arcade rooms, which also benefit from his Lucky Foot item.
When playing as Cain, always find, purchase, and consume as many pills as you can. The only negative pills you can get while carrying his Lucky Foot are Bad Gas, Explosive Diarrhea, and Bombs are Key, meaning every pill you get is as good as a normal stat+ treasure or something like I Found Pills or Puberty.
NOTE: Cain's Lucky Foot will NOT enhance his odds at winning a slot machine. It only changes the odds of the Shell game.
Completing The Womb with Cain unlocks the Sack Of Pennies.
Completing Sheol unlocks the Bomb Bag.
Completing The Cathedral in Wrath of the Lamb unlocks Abel.
Completing The Chest unlocks Cain's Eye.
- Keeping consistent with his eye patch, Cain's tears only shoot from his uncovered eye with a slightly lopsided trajectory path.
- For the same reason, if Cain acquires Technology 2 (which would go over his patched eye), he will get an unique boosted version of Technology instead. If Cain is paired with Technology 2 and Brimstone, Brimstone can still be charged, but not fired. Technology will fire continuosly unless leaving a room or picking up an item.
- Cain and the familiar Abel (that is unlocked by beating the Cathedral with Cain) are a reference to the Biblical brothers of the same name. His eye patch might hint at Cain's sinful nature and the murder of his brother, after which he was uniquely cursed to walk the Earth forever, but never be harmed. Hence the Luck Foot and it's effect on pills.
- He is referred to as the "thief" in the Unholy Edition art booklet, with increased speed, less HP, Lucky Foot, and a key (presumably a reference to a lock pick).