Binding of Isaac: Rebirth Wiki

(in Repentance)

Crystal Key is an unlockable trinket added in The Binding of Isaac: Repentance.

Effects[ | ]

  • Whenever Isaac clears a room, has a chance to open a neighboring Red RoomRed Room.
    • This effect can occur while Isaac is inside a Red Room, but the chance is smaller.

Notes[ | ]

  • It's possible to increase the chance of a Red RoomRed Room unlocking if multiple Crystal Keys are held, e.g. from absorbing using Collectible Smelter iconSmelter, holding Collectible Mom's Box iconMom's Box, having a golden Crystal Key, or other methods. The chance for a Red Room door to unlock depends on the number of Crystal Keys held and if the room cleared is normal or Red.
Crystal Key Count Normal Room Red room
1 33.3% 12.5%
2 50% 16.6%
3 100% 25%
4 100% 50%
5 100% 100%
  • Each cleared wave of a Challenge RoomChallenge Room has a chance to generate an adjacent Red Room.
  • Rooms that are re-fought using the Collectible D7 iconD7 have a chance to generate additional Red Rooms.
  • Doors do not have to open to an actual valid Red Room, and can lead outside the map and into an I AM ERRORI AM ERROR Room.

In-game Footage[ | ]