Rei has neck-length light pink hair that is tied in a side ponytail on the left side, brown eyes and she is slightly taller than Yuu.
Rei is a understanding and supportive sister to Yuu, with whom she is close. She quickly comes to suspect Yuu's relationship with Touko is more than simply platonic and does her best to help them both with advice and support. When she isn't being serious, she enjoys affectionately teasing Yuu whenever she gets the chance.
Rei has been dating Hiro ever since high school where she was the one who confessed to him, which is partly because they were intimate before being official and partly because she didn't want someone else to ask him out.
- The name Rei means "wise" (怜 rei).
- Rei's surname Koito means "small" (小 ko) and "yarn" (糸 ito).
|Yuu Koito • Touko Nanami • Sayaka Saeki • Akari Hyuuga • Koyomi Kanou • Seiji Maki • Suguru Doujima • Natsuki Sonomura • Manaka Yoshida • Midori Igarashi • Chie Yuzuki • Serizawa • Oogaki|