isaac: Isaac is the titular character in The Binding of Isaac as well as the first available character in default. Issac's stats are well balanced, making him a great all-around character.

madgalene: Magdalene, sometimes known as Maggy for short, is an unlockable character in The Binding of Isaac. She is unlocked by having seven heart containers of maximum health at any one time in a playthrough

cain: 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

eve: Eve is the sixth unlockable character added in the Halloween Update. She is unlocked by making two or more deals with the devil in one playthrough.

azazel: Azazel is a character unlocked by making three deals with the Devil in one run. Azazel starts with a short-ranged version of Brimstone which deals damage (except in Repentance) 13 times in one second

apollyon: Apollyon is a character added in The Binding of Isaac: Afterbirth †. He is unlocked after defeating Mega Satan for the first time. Apollyon starts with two Red Heart containers and Void.

the lost: The Lօst is a secret character. The Lօst starts with no health and cannot gain health by any means. Therefore, he will die from any damage taken.

lilith: Lilith is a character added in The Binding of Isaac: Afterbirth. Lilith starts with one red heart container and two Black Hearts. Lilith's starting items are the Box of Friends, Incubus, and Cambion Conception. Lilith is permanently blindfolded, meaning she has no ability to fire tears; she instead deals damage with the Incubus familiar that follows her. Lilith is unlocked by completing Greed mode with Azazel.

lazarus: Lazarus is a character unlocked by having four or more Soul Hearts (or Black Hearts) at once during a run. He was introduced in The Binding of Isaac: Rebirth. He starts with three red heart containers and a double-blue pill with an unidentified effect. He has slightly lower Range and Luck than Isaac but also starts with an extra life. His revived form has increased base stats, with above-average damage, speed, and range. Though low on health, his improved stats counterbalance this weakness well.

bethany: Bethany is a character added in The Binding of Isaac: Repentance. She is unlocked by defeating Mom's Heart or It Lives in hard mode with Lazarus without losing a life. Bethany starts with three Red Heart containers, four soul charges (2 Soul Hearts), and Book of Virtues. Bethany is unable to utilize Soul Hearts and Black Hearts as health. When picked up, they instead are converted to a resource unique to Bethany called "soul charges" at the rate of one charge per half heart. The number of soul charges currently owned is listed along with the pickup counters. Soul charges can be consumed to use Bethany's activated item when the item isn't fully charged, at the rate of one soul charge per empty bar of charge.

keeper: Keeper is a secret character added in The Binding of Isaac: Afterbirth. Keeper is unlocked by donating 1000 Coins to the Greed Donation Machine. Keeper starts with 1 Bomb and a triple shot similar to The Inner Eye.

the forgotten: The Forgotten is a secret character added in Booster Pack #5 that resembles a Bony. He cannot fire regular tears, and instead has a bone club that can be swung as a melee weapon or charged to be thrown. The Forgotten cannot acquire regular heart containers. Any regular heart containers acquired will be turned into Bone Hearts, and any Soul Hearts or Black Hearts will be given to The Soul. The Forgotten and The Soul share a health bar, so each form has a maximum of 6 hearts instead of the regular 12.