Chapters are sets of floors that contain similar enemies, themes, bosses, and difficulties. Chapters are divided into two floors.
Antibirth introduces four new chapters, which come with higher risk in exchange for higher reward. After unlocking "A Secret Exit", locked doors to the new chapters will appear upon defeating bosses in the first three chapters.
- All Treasure Rooms in these chapters will contain 2 items for Isaac to choose from.
- Harbingers will not appear in these chapters, even if Book of Revelations is used.
- Bosses in these chapters can be replaced by The Fallen.
|Chapter 1||Chapter 2||Chapter 3||Chapter 4|