Wikia

For details about every stat check Stats

Character	Health	Speed	Tears	Attack	Range	Starting items	Info	Biblical reference
Isaac	3	2	2	2	2	x1 Bomb The Dice (unlocked after beating The Womb with ???)	Default, first character. Base speed of 100%	The son of Abraham who God asked to sacrifice in Binding of Isaac.
Magdalene	4	1	2	2	2	Yum Heart	Unlocked by having seven or more Heart Containers in one playthrough (Soul Hearts do not count). Base speed of 85%	One of Jesus's friends. Also known as Mary.
Cain	2	3	2	3	1	x1 Key Lucky Foot	Unlocked by having 55 or more coins at any one time in one playthrough. Base speed of 130%	Son of Adam and Eve, brother of Abel.
Judas	1	2	2	4	2	x3 Penny The Book Of Belial	Unlocked after defeating Mom's Heart for the first time. Base speed of 100%	Judas Iscariot, the one who betrayed Jesus Christ.
Eve	2	3	2	1	2	Dead Bird Whore Of Babylon	Unlocked by making two or more deals with the devil in one playthrough, even if it kills you. Base speed of 123%	First female created by God.
???	-1	2	2	2	2	x3 Soul Hearts The Poop	Unlocked after defeating It Lives. Can not have hearts. Items that would normally increase max health add Soul Hearts instead. Normal heart pickups and healing has no effect. Base speed of 110%	None (Reference to Edmund McMillen)
Wrath of the Lamb DLC
Samson	1	2	2	2	2	x1 Soul Heart Bloody Lust	Unlocked by skipping two Treasure Rooms and defeating Mom. Base speed of 110%. Base tear speed of 131%	He was born into the world by God to defeat the Philistines, but had his hair cut off because it was one of the three sources of his power (along with not drinking wine or satisfying sexual desire). He was blinded after revealing his secret.

Magdalene, Cain and Eve unlock as soon as their criteria are met, you do not need to beat the game to unlock them. Eve is the only character in the game who starts with two passive items.