|“||And Adam knew Eve his wife; and she conceived, and bare Cain, and said, I have gotten a man from the Lord.||”|
Cain (ケイン Kein) 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).
Cain is missing his left eye, so he'll only be able to shoot with his right one. This also makes it impossible for him to shoot tears (including special tear effects like Brimstone) while using Technology 2 (though its damage will be significantly buffed). Chemical Peel gives a 50% chance of shooting a blood tear instead of a normal one. However, he still shoots the standard multiple tears with Mutant Spider and The Inner Eye.
Cain's Lucky Foot gives him roughly a 50% chance of winning the Shell Game rather than the normal 33% chance. The chances of the Slot Machine giving items is also increased. This makes it very easy for Cain to "farm" the Arcade room for items and money. Using the Blood Donation Machine to make money to spend on the Shell Game/Slot Machine will frequently be net-positive for Cain, and he can continue spending money and hearts until either the Slot/Blood Donation Machine or the Shell Game vendor explodes/provides Skatole.
The Lucky Foot also turns negative pills into positive pills, but will not affect neutral pills such as Pretty Fly, Telepills, Bombs are Key, I Found Pills, Puberty, Bad Gas, or Friends Till The End. This makes Mom's Bottle Of Pills a much better item. (Does not apply in Rebirth and Afterbirth).
- Keeping consistent with his eye patch, Cain's tears only shoot from his uncovered eye with a slightly lopsided trajectory path.
- Even though he has an eye patch, he still cries from his covered eye, this might be because Isaac himself is wearing a eye patch.
- Cain and the familiar Abel 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 Lucky 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).
- Cain's Eyepatch - Hold 55 Coins at once in a single playthrough.
- The Bag - Kill Mom's Heart with Cain.
- The Bomb Bag - Kill Satan with Cain.
Wrath of the Lamb
- Abel - Kill Isaac with Cain.
- Cains Eye - Kill ??? with Cain.
- Eternal Cain - Complete the game with Cain in Hard Mode.
- A Bag of Pennies - Defeat Isaac.
- A Bag of Bombs - Defeat Satan.
- Abel - Defeat The Lamb.
- Cain's Eye - Defeat ???.
- Cain's Other Eye - Complete the Boss Rush.
- Glass Baby - Defeat Mom's Heart or It Lives on Hard Mode.
- D12 - Defeat Hush.
- Evil Eye - Defeat Ultra Greed
- Green Baby - Defeat Mega Satan.
- Picky Baby - Earn all Hard Mode Completion Marks.
Cain starts with the Lucky Foot, medium health, and high damage output. Cain's strength lies in his versatility, his relatively balanced attributes make him well-suited to a variety of play styles.
The easiest way to unlock Cain is to use the Slot Machine until it explodes and provides A Dollar, which will instantly unlock him upon pick-up. The 2 Of Diamonds Suit Card is also useful, since it doubles the player's current Coins. Another strategy is to use the Blood Donation Machine while playing as Maggy.
- Cain is an excellent character to start with if you want to assemble the Pill Popper combo (Mom's Bottle of Pills + 9 Volt, The Battery, or the Habit), as his Lucky Foot guarantees you only positive or neutral pill effects. Mom's Coin Purse is useful for the same reason. D20 can prove immensely useful in the Arcade or coin-knocking enemies as large amounts of pickups are spawned in a single room and rerolling D20 has quite a chance to spawn a pill.
- Cain is tied with Eve for highest starting speed. Use this to your advantage; Cain is a capable hit-and-run character. Zip into combat and zip out again; your low range won't even matter if you can dodge well (and if you can't, Cain's a good character to practice with; he's more forgiving of mistakes than Judas).
- Cain's hit-and-run playstyle allows him to make use of burst-damage tears, i.e. Mutant Spider.
- Always go for the shell game in the Arcade first; the Lucky Foot means that you have a higher chance of winning the shell game than the slots.
- While in an Arcade, try to use the Blood Donation Machine to convert any leftover hearts you win into coins. Don't be afraid to donate health until you're down to one or two hearts, since the donation machine will often explode and leave the Blood Bag as a reward. Doing this for a few levels significantly raises Cain's health and therefore especially helps making deals with the devil more feasible.
- Soul Hearts can offset Cain's lack of durability; as always, keep an eye out for Tinted Rocks and blow them up.
- As Red Chests have a chance of dropping 2 pills, Curse Rooms have higher chance of paying off.
- If you find a Fortune Telling Machine, use it as much as possible, as Lucky Foot gives 100% chance of item drops from it.
- PHD (redundant with your starting item, although it does identify pills before you use them, along with the healing)