Kōhei Izumi/Relationships

Takeru Yuiga
Izumi is often seen physically grabbing and attacking the gunner. Even so, Izumi unleashes Yuiga upon Osamu when he asks how he can become a better shooter, showing that he still had some amount of confidence in his abilities.

Yuu Kunichika
It seems that Izumi wants Kunichika to address him by his first name.

Shun Midorikawa and Yōsuke Yoneya
Izumi, Midorikawa, and Yoneya are seen together very often, especially at the start of the series. They like messing around, and tease each other for their misses. Izumi's nickname "tama-baka" and Yoneya's nickname "yari-baka" comes from this trio. Oddly, it seems that Izumi doesn't necessarily want to be addressed by his first name by Yoneya.

Osamu Mikumo
Osamu goes to Izumi as a fellow shooter, seeking help for his general fighting skills.

Masataka Ninomiya
After being approached by Ninomiya, Izumi acts as his mentor. It mostly seems that he taught Ninomiya how to make composite bullets.