Mushroom

Mushroom (マッシュルーム, Masshurūmu) is the B-Class Rank 93 professional hero for the Hero Association, and the hero in charge of H-City, together with Horse-Bone.

Appearance
Mushroom has black hair styled in a bowl-cut. Mushroom sports a black mask, covering their eyes and a black shirt with shoulder padding shaped as mushrooms along with a white cape.

Rumored Monster Arc
As the higher-ups of the Hero Association discuss the status on the cities, Mushroom was mentioned as a hero in charge of H-City. Their report on the city was "all quiet here".

Omake (Volume 8)
A monster that was being transported to prison mentioned it was defeated by Mushroom.

Abilities and Powers
Mushroom can defeat weak monsters alone, implying he is fairly strong. And considering he is co-in charge of H-City means the Hero Association trust in his strength to a decent degree.