Companion Cube is a recommended character recommended by Nelsa13luv. He/She appeared in Reveal Novum. He/She is also seen in BFDIA 5b in levels 8, 9 and 10. Its last appearance is in level 10, where it was sadly fell off but no choice to pass the level.
- In BFDIA 5b, at level 10, Book have to activate a lever that makes the platforms under the Companion Cube disappear so she could complete the level, which killed the Companion Cube, similar to the actual game Portal, in which the game Companion Cube was in, where the Companion Cube must also die so the character could complete the level.