Grim is a magic-wielding monster who serves as Yuu's partner. He has a big mouth, and easily gets carried away.
(translated by ame)
Grim very closely resembles a cat. His fur is grey with a white patch at his chest and pink paw pads, and he has electric blue flames blazing from his ears. His eyes are also bright blue. Around his neck, he wears a black-and-white striped bow tie which is torn at the ends; it also bears a light purple gemstone that rests against his chest. His tail is shaped like a pitchfork.
The first time the prefect met Grim, he has an impression of being incredibly devilish and mischievous, causing trouble wherever he goes. It is also noted that Grim would do things to extreme lengths to achieve the things he desired, such as burning the welcoming ceremony hall to show off his magic in an attempt to get accepted in NRC. He is somewhat shown to be quite narcissistic and prideful, often bragging about his magic abilities. He is noted to also like getting attention from people, as he joined Magical Shift tournament just so he can get exposure through the show. Aside from that, he is also somewhat easy to impress and quite curious of things he is unfamiliar with, such as learning about the 7 figures of NRC. He is also surprisingly easy to taunt, such as when Ace insulted the (soon-to-be) Prefect and Grim for not knowing who the 7 villainous figures are. Grim is shown to enjoy teasing people around him, most notably the player, Ace, Deuce, and other people as such. As the story progresses, he starts to enjoy the company of his friends and the prefect.
When Grim ate the black stone from the leftover from Jamil's overblot, he starts to act very strange and became addicted to eat more black stones.  Grim's behavior becomes more unstable after he ate the stone left from Vil's overblot and grows more hostile. When he sensed Yuu nearby at the colosseum, Grim attacked Yuu in his belief that they were there to steal the stone from him.
- His name may be a reference to Grimm's Fairy Tales, a popular fairytales collection which includes the tale of Snow White, Sleeping Beauty, and so many more.
- Grim can use fire magic.
- Main Story Episode 4-37
- Main Story Episode 5-75