Tomonari Mashima

Appearance
Tomonari is a tall adult male with brown hair and green eyes. His normal outfit consists of a black blazer with a dress shirt underneath, black pants, and a tie.

Personality
Tomonari is a man who takes his job seriously. He is the English homeroom teacher of Class A, and is well respected by his students. He is a man who sticks to his morals without compromise and is dedicated to helping students. He was angry when he heard from Kiyotaka that Tsukishiro was responsible for Suspension of Chairman Sakayanagi, already having opposed the new Chairman due to conflicts within ideals that he was willing to stand up for. He is one of the few teachers who was willing to take a stand against Tsukishiro as well, even before Kiyotaka had confronted Sae and him, showing that he is a very virtuous person.

Background
Some years ago, Tomonari attended Advanced Nurturing High School. He was in the same school year as Sae Chabashira and Chie Hoshinomiya, but he was not in the same class as the two.

Once he chose the path of becoming a teacher similarly as his fellow peers, they became friends. According to what Chie said in a drunken state one night, he is her best friend. It is unknown whether this was simply due to the alcohol or whether it's her true feelings on the matter.

Plot
During the Island Special Exam, Tomonari explained the rules of the exam and subsequently announced the final point totals.

In the following week after the Island Special Exam had ended, he explained the contents of the Zodiac Special Exam to Kiyotaka Ayanōkoji, Kei Karuizawa, Teruhiko Yukimura, and Hideo Sotomura. While on the cruise, he met up with Sae and Chie to chat for a bit during their time off, but Kiyotaka ended up overhearing their conversation. Both Tomonari and Chie were suspicious of Sae's involvements with Kiyotaka, but he soon warned Chie that he wished for his colleagues to protect their morals in order to avoid reporting on a colleague's failure.

Name Etymology

 * The name Tomonari consists of kanjis that mean "wisdom, intellect" (智) (tomo) and "to be, also" (也) (nari).
 * In one of the illustrations for Volume 10 of the light novel, 智也 is spelled as Tomonari (ともなり). However, on the official website, it is spelled differently as Tomoya (ともや).
 * This article uses the spelling from the light novel but it can be subjected to change in the future.
 * Tomonari's surname Mashima consists of kanjis that mean "real, geunine" (真) (ma) and "island" (嶋) (shima).