Haruki Yamauchi/Relationships

Ken Sudō
Ken is one of Haruki's friends in D-Class and they are often seen hanging out. Part of the 3 Idiots of D-Class along with Haruki Yamauchi and Ike Kanji.

Kanji Ike
Kanji is one of Haruki's friends in D-Class and they are often seen hanging out. Part of the 3 Idiots of D-Class along with Haruki Yamauchi and Ken Sudō.

Arisu Sakayanagi
Their first encounter was during the Mixed Training Camp Special Exam in Volume 8, where Yamauchi was chatting with his friends and didn't notice Sakayanagi calling out to him to look out which leads to them colliding with one another, Yamauchi offered to give Sakayanagi a helping hand but she refused and told Yamauchi there was no need for his concern. He soon left saying to his friends that Sakayanagi was cute, but clumsy.

In Volume 10, it was revealed that Arisu was not as forgiving as first thought and was the main reason behind his expulsion. Turns out, she held a grudge against him for making that snide and rude remark when they had collided. She masterfully controlled him by pretending that she was interested in him and took away all his pride by showing what type of person he truly was to his class.