Lost Soul

For the trinket with a similar name, see Found Soul. For another trinket with a similar name, see Your Soul.

Lost Soul is a passive item added in The Binding of Isaac: Repentance.

Effects[]

Gives Isaac a small soul familiar that closely follows behind him. If the soul takes damage, it dies, respawning at the start of the next floor.
If the soul survives to the start of the next floor, it spawns one of the following:
- 3 soul hearts.
- 2 eternal hearts.
- An item from the Treasure Room or Angel Room item pool.

Floors completed during the Ascent count.
It is advised to skip picking up the item until after you clear the floor, in order to guarantee rewards.
After the Mother's Shadow chase, the Lost Soul familiar will be revived allowing you to have a second chance at a reward.

BFFS!: Gives the Lost Soul Holy Mantle.
Forget Me Now: Restarting a floor triggers the Lost Soul if it is alive.
Tainted Isaac: Swapping Lost Soul for another item and picking it back up again will cause it to respawn if it died previously.

Bursting Sack Does not provide immunity to contact damage from spiders to the Lost Soul.

Bug!	If the Lost Soul is killed before the chasing with Mother's Shadow, it will respawn after you leave the place containing Knife Piece 2 safely.

Bug!	When playing as Tainted Lazarus, if Lost Soul is killed, it will respawn on the same floor it died on as soon as Tainted Lazarus flips again.

Bug!	Lost Soul can die if it touches projectiles generated by friendly enemies (spawned from Mystery Egg, for example).

Bug!	Lost Soul will give rewards when moving from the starting room of a floor to the previous floor with Glowing Hour Glass twice.

The Lost Unlocks