Grim is a playable Exosuit of the Atlas Brigade on Project Exonaut. His Weapon Mod increases the clip size of the Wildfire. Grim is available for purchase at level 40 for 5000 coins. Starting at October 17,2011 Grim was unlocked along with Marceline in the Halloween Slam event.
In The ShowEdit
In his show, Grim was the Grim Reaper. He was trying to reap the soul of a hamster, but two children--Billy and Mandy--got in the way. They challenged him to a Limbo contest, so if he won, he could reap the hamster's soul but if they won, he'd have to be their "best friend" forever, although they treat him like a slave.
In his show, Grim is a skeleton wearing a black and red cloak, sometimes with a scythe. In Project: Exonaut, Grim is a man with red stripes and pitch-black skin. He has a red spiral on his chest and a skull on his belt, with a Red Visor on his helmet.