3. Speed o' Sound Sonic

Sonic is an anti-hero who appeared in the 4th episode of season 1, he was originally hired to kill the Paradisers and their leader Hammerhead. He kills all of them except him, who escaped due to his thick skull. Saitama later turns up and Sonic mistakes him for a Paradiser because of his bald head. Sonic's abilities are no joke either, his speed can hit the sound barrier and the only person able to compete with his speed is Saitama of course. And because Saitama can keep up with Sonic, he accidentally hit Sonic in his *REDACTED*, which forced Sonic to retreat, but before then he promised Saitama he would get stronger and kill him.