Speed-o’-Sound Sonic, a human ninja hailing from a clandestine Ninja Village, emerged as the sole survivor of the 44th graduation class after enduring his village’s brutal training regimen. Renowned for surpassing sonic velocity, his superhuman agility and signature ninjutsu—afterimage illusions and explosive shuriken—earned him his moniker. His striking appearance features a lean frame, a black topknot, and vivid purple markings beneath his eyes, complemented by a tactical black uniform reinforced with metal plating and a draped purple scarf. Initially employed as Zeniru’s bodyguard against the Paradise Group, Sonic clashed with Hammerhead before a fateful encounter with Saitama ignited an obsessive rivalry. Repeated defeats—marked by humiliating groin strikes, hospitalizations, and imprisonments—fueled his relentless training and unorthodox pursuits of power, including ingesting a monster cell rendered inert by his decision to cook it first. A strategist at heart, Sonic wields a ninjato, kunai, and specialized shuriken with lethal precision. His techniques range from the Wind Blade Kick, channeling rotational force into crushing blows, to the Ten Shadows Burial, which overwhelms foes with ten simultaneous afterimages. Spin-off media like *One Punch Man: A Hero Nobody Knows* expand his arsenal to include the Hail of Carnage, a barrage of explosive projectiles, and Mode Change, granting temporary invisibility and heightened speed. Though often adversarial, Sonic exhibits pragmatic shades: he alerted Genos to the Deep Sea King’s danger and allied with Puri Puri Prisoner to quell a prison riot. His arrogance and fixation on combat clash with sporadic compassion, such as befriending bear hunter Frank and adopting the piglet Ino. While dismissive of heroes, he recognizes their inadequacy against overwhelming threats. Sonic’s narrative arc underscores his ceaseless drive to topple Saitama, juxtaposing his disciplined ninja upbringing against impulsive battle choices. This tension between ambition and limitation, paired with tactical adaptability and moral ambiguity, cements his role as a layered and unpredictable figure within the series’ conflicts.