Speed of Sound Sonic is the foremost antagonist of One Punch Man.
AboutHe was ninja who delecaled himself as Saitma's rival is first hired by Mr. Monier as bodyguard defending him from a group calling themselves the Paradise Group including leader Hammerhead who is terrorist and cowardldy man. when Saitima and his parenter Genos came the scene appocing by Sonic who fight with them. Saitima breaking Sonic;'s sword by biteing it subsequently Sonic beatyted Hammerhead and his boss Mr. Monier. Saitma tried explme to Sonic that he was hero work hard to defened the city but Sonic wouldt listen
Sonic was arrested and quickly sent to the prison but manages to break out several times by escapeing it, he deafted prsionsers who tried killed them