|Born||August 9, 1997 (age 24)|
(1 year, 3 months and 21 days)
|Group||t-smile / MRK43 (Team M)|
Koushun Arimasa was a member of MRK43's Team M.
- Minna, watashi no sekai e yokoso!!!
- (Everyone, welcome to my world!!!)
t-smile Senbatsu Elections
- 1st Senbatsu Election - #27 (Next Girls)
t-smile Janken Tournaments
- Motto: Do the best while you can stand on your own.
- Hobbies: Playing Badminton
- Specialty: Singing
- Favorite animal: Tortoise
- Favorite artist: Ikimono Gakari, Porno Graffiti, SCANDAL, Mizuki Nana
- Favorite movie: Matilda, Thread of Lies
- Favorite book: Sherlock Holmes
- Favorite season: All seasons
- Favorite place in the house: My room
- Favorite food: Pizza
- Disliked food: None
- Superstitious practices: None
- Future ambition: To be a YouTube singer and voice actress
- Team M → Graduation