Shirayuri Koyomi

Koyomi Shirayuri (白百合 こよみ) is a minor character, the classmate of Yūki Rito in both his first and second year. She is often seen hanging around with Arai Sayaka. She and Koyomi are Sairenji Haruna's fellow members of the tennis club.

Appearance
Koyomi has brown pigtails and brown eyes in the manga (black hair in the anime).

Plot
Koyomi has very little involvement with the plot, though she is one of the more significant named minor characters in Sainan High. Most of her appearances are for fanservice sake.

Arai Sayaka
Koyomi is often seen hanging with Sayaka. They're both a member of the Sainan High tennis club and they are best friends. The "After School" one-shot make clear Koyomi is in love with her while Sayaka don't like when she become too close.

Etymology

 * Shirayuri means "white" (白) (shira) and "lily" (百合) (yuri).

Her surname might be a hint on her sexual interest in same sex (with Arai Sayaka).