|Series||The Grim Adventures of Billy and Mandy|
|Nano Item||Shrunken Head|
|Voiced by||Greg Eagles|
Grim, or "The Grim Reaper", is the embodiment of death who was tricked into becoming the friends of Billy and Mandy for eternity after losing in a limbo match over the soul of their hamster. After living with Billy and Mandy for quite some time, he became accustomed to a simple life and began to grow attatched to them, but would never admit it.
In FusionFall he has opened a chain of soul replenishing spas called the Grim Gardens, that became immensely succcessful as Princess expressed desire to purchase it. However, in the wake of the Fusion invasion, Grim was able to slip away from both of the children to take a vacation in Orchid Bay in the past.
Unfortunately, Grim's means of escape quickly became more trouble than it was worth. Grim is unable to enjoy his vacation since Fuse's invasion reached the shores of Orchid Bay, and stole his collection of Zuni heads as a means to create Fusion Grim.
In addition, rumors have been spread about Grim being a traitor, despite the fact that Grim donated many "Resurrect 'Em" spots to revive fallen players. These rumors started when the player, acting to help Numbuh 1, found a tape of Fusion Mandy encountering him, trying to recruit him to their side, but he refused.
In spite of the rumors, Dexter trusts Grim to help him find missing heroes who disappeared during the invasion, curious to see if the heroes have fallen in battle. After having his Zuni heads recovered, and utilizing the "Desk Lamp of Hades", Grim reports that the heroes are not in the land of hades, but it was later discovered that Fusion Demongo stole the powers.
He is still alive in the future due to the presence of him at Resurrect Em's (because he's technically dead in the first place and now there is no future). However, he himself is nowhere to be found. In the past, his Nano is one that has group only abilities besides Darwin.
In the future, there is a possibility that he saved Billy and Mandy from destruction because of their pact, or it could be also that Billy and Mandy didn't survive the invasion and thus their pact was broken.