Ouse Yumiko

Masaru's classmate and also Akira's childhood friend. She lost her parents in a traffic accident when she was a child and now is living with her uncle, who works as a teacher at Kashima school and, according to her, is really kind and gentle always helping her when she needs it.

It's not very unusual for her to be absent from school due to her very sudden fits of asthma, a chronic disease she holds.

Spoiler

She actually holds feelings for Yukinojou from the time he saved her during one of her asthma attacks, albeit he barely remembers her by now.