The Binding of Isaac: Antibirth Wiki
Lost Soul
Lost Soul Icon.png
Character Appearance
Lost Soul App.png
Item Type
Passive Collectible
Item ID
Pickup Quote
Protect him
Item Pool
Treasure Room
Unlock Method
Lost Soul Defeat The Witness as The Lost.

Lost Soul is a passive item.


  • Spawns a familiar version of The Lost that follows Isaac.
    • Upon being hit, it instantly dies, regenerating on the next floor.
    • If it survives an entire floor, it grants a random reward.


In-game Footage[]



E4P8 8E02 (First floor treasure room)

Bug Bug! When you have one Lost Soul and it dies, quitting and re-entering the game will cause it to respawn alive, but quickly die after.
Bug Bug! If you somehow manage to get another Lost Soul item (using an Othala rune to duplicate Lost Soul), there will be two Lost Soul familiars. If both Souls die, quitting and re-entering the game will cause one to respawn and die, but the other will stay alive. Doing this again will have both souls stay alive. This can be used after the floor's boss fight to get the reward for two Lost Souls on the next floor.