Manako

He is an unnamed monster of the Monster Association who was first seen using the toilets. He was then taken hostage by Flashy Flash and Saitama to lead their minecart.

Appearance
The monster is short and round, with light skin and one large eye. He also has two small horns, sharp teeth and wears a thick black belt.

Monster Association Arc
The monster is using the restroom, when Saitama and Flashy Flash came and took him hostage, using the monster to lead them to the Monster King lair.. As the monster was leading them through the tunnels, his plan was to de-rail them at a switching point to kill the heroes and himself,but changed his mind after seeing the large fall.

Soon after, the trio pass an excavation site in the Monster Association HQ, there the other monsters attack, but were quickly killed by Saitama and Flashy Flash. The monster almost fell to his death, but was saved by Saitama, after the hero sacrificed the gold he tried to take.