Binding of Isaac: Rebirth Wiki

Added in Afterbirth †

Duality is an unlockable passive item added in The Binding of Isaac: Afterbirth †.


  • Whenever a Devil Room Devil Room/Angel Room Angel Room spawns after defeating a boss, the other will also spawn.
    • Upon entering one, the other one will disappear.
    • Both rooms will spawn even if a devil deal was made before.
    • In rooms without enough accessible walls, only one of the two will spawn.


  • Even with Goat Head Goat Head or Eucharist Eucharist both rooms will not stay open, and entering either of the rooms will make the other disappear.
  • If Duality was bought through a Devil deal, it is still possible to get Angel Room Angel Rooms as well as Devil Room Devil Rooms.
  • Teleportation via a Joker Joker card, a Red Chest Red Chest or a Sacrifice Room Sacrifice Room before defeating the boss and choosing a door will follow the normal rules of Devil/Angel Room generation, instead of a 50/50 chance.
    • The room that was chosen this way will be the only one that opens once the boss is defeated.
    • Teleporting after choosing a door will always take you to the same room.



  • Tainted Lazarus Tainted Lazarus: The Lazarus that fights the boss must be the one holding Duality in order for it to trigger.

In-game Footage[]


  • Duality is one of only five items to appear in both the Angel and Devil item pools, the others being 7 Seals 7 Seals, Lil Delirium Lil Delirium, Void Void and Added in RepentancePurgatory Purgatory.
  • The Duality image appears to be similar in concept to the yin and yang symbol of Ancient Chinese philosophy, as the latter represents the concept of dualism as well. However, they don't quite appear to be exact in terms of the diameter format.