If the player does not have a sixth accessory slot yet, the Celestial Onion can be used, and it will grant the sixth accessory slot. If in Expert Mode, the seventh slot will not be granted until the player also consumes the Demon Heart.
- If the Demon Heart has also been consumed, the seventh slot does not appear in the player's inventory while in Normal Mode, whether there's an item inside it or not.
- It does nothing if a seventh accessory slot (or more) has already been obtained through the use of other mods.
- In previous versions of the mod, the onion toggled the Prepare to Die/Cry mode instead.
- Additionally in previous versions of the mod, the slot granted by the Celestial Onion was only functional in Expert Mode worlds, like the one granted by the Demon Heart.
- In the mod's source files, the onion is referred to as 'MLGRune2' in reference to its previous function.