Rumi Yokoi

, 横井るみ

Yokoi is a girl who sits near Seki-kun, but tries to ignore his unusual actions despite being drawn to them. She enjoys crocheting and excels at it, while her drawing abilities are poor and she remains unaware of this.

Spoilers:

She befriended Toshinaris little sister Jun, and even came to Sekis house to play with her. During parent visitation day she also joined forces with Sekis mother in preventing Seki-kun from playing during class.