▾Table of Contents▾
Lost Soul item
Lost Soul is an unlockable familiar in The Binding of Isaac, added in the Repentance DLC.
Description
Spawns a familiar that follows closely behind Isaac and dies in one hit, respawning at the start of the next floor.
If the familiar survives and is taken down to a new floor, it will rewards Isaac with one of the following:
• 3 
Soul Hearts.
• 2 
Eternal Hearts.
• 1 item from the Treasure Room or Angel Room item pool.
Has a 1% chance of being dropped upon defeating Blighted Ovum.
Note
This page shows the latest information as of the new Repentance+ (Online Co-op) DLC.
To see information about this item for the previous Repentance version, check this page instead.
How to unlock?
Defeat Mother as The Lost.
Item pools
Lost Soul can be found in the following item pools:
| Name | Weight |
|---|---|
| Treasure Room |
1.0/1.0
|
| Secret Room |
1.0/1.0
|
| Greed Treasure Room |
1.0/1.0
|
| Greed Secret Room |
1.0/1.0
|
| Baby Shop |
1.0/1.0
|
Tags
The following tags are applied to this item:
| Id | Description |
|---|---|
| uniquefamiliar | Cannot be duplicated via  Box of Friends. |
| summonable | Can be summoned via  Lemegeton. |
| nocantrip | Not available as card effects during the Cantripped! challenge. |
Special synergies
The following special synergies and interactions for Lost Soul have been documented.
| Mod | Item | Synergy |
|---|---|---|
| --- | BFFS! | Gives the Lost Soul a once-per-room  Holy Mantle shield. |
* Note that not all possible synergies and interactions are listed here.
YouTube video
External links
- Check out the item description on the external Isaac Wiki.
Eternal D6 
Bird Cage 
Larynx 
Blood Bombs 
Lil Dumpy 
Bird's Eye