Tsumori seems to enjoy teasing Hiroki and Nowaki in their relationship, usually by being clingy and affectionate towards Nowaki intentionally to make Hiroki jealous. However, he has no romantic feelings for either of them, so his motives for this are so far unknown.
He and Hiroki have a very cold relationship, which began when Hiroki found him and Nowaki sleeping naked on the floor together. Although this proved to be a misunderstanding, this caused Hiroki to see him as a threat to their relationship. Hiroki refers to him as the "flirty senpai" of Nowaki.
|Junjou Romantica characters|
Eri Aikawa • Ryuuichiro Isaka • Kaoru Asahina • Kyo Ijuuin • Ryou Shizukuishi • Haruhiko Usami • Kaoruko Usami • Fuyuhiko Usami • Mizuki Shiiba • Tanaka • Takahiro Takahashi • Keiichi Sumi • Shinosuke Todo • Risako Takatsuki • Tsumori