MaeIso

MaeIso is the slash ship between Hiroto Maehara and Yūma Isogai from the Assassination Classroom fandom.

Canon
Maehara and Isogai are canonically childhood best friends and neighbors. Their friendship dated years before the start of Assassination Classroom, making them the oldest friendship in the Class of 3-E.

When Maehara gets kneed in the stomach by Takaoka for speaking up against him, Isogai looks worried and is the first to help Maehara. They are later seen together again, taking care of each other after Maehara recovers.

They are still friends after graduation, appearing even friendlier than they were in school.

They are seen going to the festival together, along with Chiba and Hayami.

On the official cover card of the fourth and final opening theme, Bye Bye Yesterday, Maehara and Isogai are in the background. The flowers petals around them resemble hearts. They are also placed next to each other in all of class 3-E's class pictures as well as all of the series' cover cards.

Fanon
They are a popular ship likely due to their aesthetic and strong friendship. People also started shipping them when Maehara talked about how great Isogai was at the cafe that the latter worked at. In one of the flashbacks, Isogai holds up a plate of goldfish to be cooked; some fans speculate that the memory is from Maehara's perspective and therefore, Isogai is feeding Maehara.

Many fans play into the theory that Maehara and Isogai do like each other in canon, but are simply too dense to realize it.

Their friendship was platonic at the beginning but turns romantic after "insert event."

It is the most written ship for both Maehara and Isogai on AO3. Their rival ships are MaeHina and IsoMegu.

Fandom
FAN FICTION 

TUMBLR

Trivia

 * Maehara and Isogai are two of the three mentioned by the girls of 3-E as "good-looking/handsome".
 * Isogai and Maehara are the top knife-users in their class, this is notable parallel to a semi-canon ship, ChiHaya, which refers to the ship between the class's top sharpshooters.