| Floors of
| The Caves|
| Base Health||400|
|Items Dropped||Boss Pool|
During the battle, Dark One will perform on of many attacks. The attacks Dark One can perform are as follows:
- Dark One will darken the room and charge across the screen multiple times, slowly moving towards Isaac.
- Dark One will fire a brimstone-laser directly down if Isaac is in that area.
- Dark One will fire tears in an asterisk pattern.