- Age: 16
- Parent: The Grim Reaper
- Killer Style: I love my baggy pants and baggy sweatshirt. They remind me of my dad's billowing cloaks and capes.
- Freaky Flaw: My temper can get the better of me and I tend to reap souls. I'm still in training so they just faint for a few minutes then wake up perfectly fine.
- Favorite Food: My dad's special roast. It scary good but I've been kinda scared to ask him were he gets the meat.
- Favorite Color: Gray, not quite as evil as my dad's black but not quite as good either.
- Favorite Activity: I love hangin' with my friends and playin' sports.
- Pet: Sickletail is my pet rat who's tail is always shaped just like my fave scythe.
- Biggest Pet Peeve: When people don't take me seriously.
- Favorite School Subject: Biteology
- Least Favorite Subject: Math
- BFFs: BoogeyJ
- GFs: I can't decide between Toralei, Nefera, or Operetta they each have their own evil quirks.
Grimz is known for his temper that causes him to reap souls. He does this in bursts of anger and feels bad about it afterwards. He likes pulling pranks with his best friend BoogeyJ. He's known as a huge flirt especially with Nefera, Operetta, and Toralei. He later develops genuine feelings for Toralei and soon start dating.
Grimz arrives at Monster High with other new students like BoogeyJ, Wicca Witch, Helga Hunch, Brian Corcillum, and Gina Djinn. He helps BoogeyJ steal a love potion to make Wicca fall for him. He flirts with many girls at school but begins dating Toralei after bonding with her over the school play. He is captured by The Masked Lantern after failing to stop him along with Wicca and BoogeyJ. He is freed after The Masked Lantern's defeat at the hands fo Gina Djinn.
He enters his senior year still in a relationship with Toralei. He is annoyed that she always drags Purrsephone & Meowlody along on their dates.He also becomes annoyed that she is still rude to other students. They both agree to change to save the relationship and fight against Gillian's army before graduation. He then begins attending MU.