Komatsu is a main character from the yuri manga Kuchibiru Tameiki Sakurairo. An alumna of the school Katō was in. A dedicated infirmary teacher, Although she applied to a different college, she went to a college where she could get credit that would count towards a medical degree, she never imagined that she'd end up working at her alma meter.
- The infirmary was a very important to her back then, because she had a friend she saw only when she was there, it was Katō.
- She remembers the time she spent with Katō at the school rooftop when she shows great care to Katō by worrying about her and praising her qualities.
- She wanted to be in the same class as Katō, but sadly Katō transferred before they switched classes, she wished that she had talked more with her, that she'd maybe see her outside the infirmary; unaware that the girl who was with her was truly Katō the ghost who takes Natsuka Ida's form temporarily to have fun memories with Komatsu again.