Seiji Shishikura/Relationships

Inasa Yoarashi
Seiji and Inasa appear to have a calm and respectful relationship. Inasa looks up to Seiji and even refers to him as "senpai". Seiji has a good understanding of Inasa's personality and tries to keep him in check when he does something without dignity.

Camie Utsushimi
Seiji is easily annoyed by Camie's easygoing personality, which contrasts with his serious nature. He often yells at her angrily only to get an empty response from his classmate. She doesn't appear to listen to anything he says and this clearly annoys him.

Even so, Seiji has displayed concern for Camie after Himiko Toga impersonated her.

Katsuki Bakugo
Seiji and Katsuki share a mutual dislike towards one another. They're polar opposites in regards to becoming heroes. Seiji believes Katsuki is vulgar and undeserving of becoming a hero. In return, Katsuki constantly makes fun of Seiji's formal attitude by calling him "senpai". He also taunts Seiji about his name and the size of his eyes.

Even after the Provisional Hero License Exam, Seiji and Katsuki still do not get along at all.

Denki Kaminari
Since Seiji watched the U.A. Sports Festival, he was aware of Kaminari's quirk being untamed and he taunts him by saying that he can't use his Quirk because it will also hurt Eijiro Kirishima and Katsuki despite of their deformed state. Denki took those insults personally especially when Seiji stepped on Eijiro's deformed body while taunting him. He ends up underestimating Denki, which leads to his defeat by Kaminari with the aid of the bodily reformed Eijiro and Katsuki.