Moge-Mu is described as being a shadow being, with a single large eye as the only visible facial feature.
In Spirituality, Moge-Mu appears at the end of the Bonus Chapter; where it appears in a white room, says something extremely cryptic, then proceeds to laugh.
In Chapter 4, Moge-Mu is mentioned by a skulking Mogeko.
In Chapter 6, the Teen Ghosts talk to Neisan about how horrible Moge-Mu is.
In the Epilogue, Moge-Mu is revealed to be the one talking to Kodi, before he begins to do something to him.
Moge-Mu is very greedy.