AsaKen

AsaKen is the Slash ship between Asaya HaseKura and Kensuke Ohshiba from the Hitorijime My Hero fandom.

Canon
When Asaya was a child, his parents divorced and he lived with his father, Seishuu Hasekura, and older sister Ayaka Houjou. His mother, Akiko, treated their family cruelly, telling them she doesn't love them and that their love for her was nothing but a burden which was holding her back. Similar to his father and sister, Asaya became depressed, and eventually developed insomnia due to Ayaka crying every night. The way his mother treated them, her attitude towards love, and the negative atmosphere of his household which he dreaded going home to, lead him to develop a deep trauma that affected his ability to feel positive emotions, particularly love of any kind, towards others. For a while the only exception was Kensuke, who he met on his way home from school when Kensuke rushed over to defend him from being bullied. Finding it easier to isolate himself, Asaya was originally hesitant to get close to Kensuke, yet he found himself becoming more and more interested each time they hung out, and quickly developed a crush on him.

He and Kensuke went to Mount Sasakure in order to scavenge and find stag beetles. They had fun, drawing a dragon on the street and catching the beetles in a small trap, until it rained suddenly and they had to hide under a small hole in an oak tree. Kensuke leaned against Asaya, making the latter get flustered and blush. The two vowed a promise to be together forever. However, that promise was soon broken when Asaya confesses that he had to move away to another school. It was revealed that he was forced to by his parents. Kensuke harshly insulted him, breaking off their friendship which dealt severe emotional blows to the two. They reunited during high school where Asaya confesses his hidden feelings for him.

Fanon
AsaKenis the most popular ship in the Hitorijime My HeroFandom due to the story being slightly about them both falling in love with each other. When the anime was airing the ship became more and more popular.

On AO3, the ship is the most written for the Hitorijime My Hero tag, as well the most written ship for both characters.