Tomonari Mashima/Relationships

Chie Hoshinomiya
Tomonari and Chie are known to be best friends and talk about each other's love interests with ease.

Arisu Sakayanagi
In Volume 11.5, Tomonari was surprised when he heard that Arisu and Kiyotaka are childhood friends. Tomonari thought that students might not like Arisu giving Kiyotaka special treatment, but Arisu did not care about his or other opinions. Arisu said this is a temporary truce and when everything returns to normal she plans to face Kiyotaka with her full strength which made Tomonari happy.

Kiyotaka Ayanokōji
At first Tomonari did not thought too much of him until Volume 11.5. He was shocked to hear Kiyotaka's account on him bein the reason behind Chairman Sakayanagi's suspension and Tsukishiro becoming the Acting Director. Tomonari, while still debating on whenever to believe this or not, considered his student's feelings and decided to help Kiyotaka. He also asked Sae what kind of person Kiyotaka is and was really surprised by him.