Speed-o'-Sound Sonic
From One Punch Man
Speed-o'-Sound Sonic is a supporting character in One Punch Man, a proud ninja assassin whose humiliation in his first meeting with Saitama becomes his entire personality: training, upgrading and returning for rematches that end the same way. He is voiced by Yūki Kaji in Japanese and Erik Kimerer in English.
About Speed-o'-Sound Sonic
Speed-o'-Sound Sonic is a proud ninja assassin from a hidden village, hired muscle with a lethal ego, until Saitama humiliated him in their first meeting. Since then, defeating Saitama has become his entire personality: training, eating monster cells, upgrading weapons, all for a rematch that keeps ending the same way. Lightning fast, endlessly theatrical and accidentally hilarious, Sonic is the rival Saitama never asked for.
Appearance
Sonic is a slim, androgynous young man with long black hair tied in a topknot, sharp purple markings under his eyes and a perpetual smug grin. He wears a tight black ninja outfit with a flowing scarf, metal guards and a katana at his back, a silhouette built for speed lines. Everything about his design cries theatrical assassin, which suits a man who introduces himself, in full, every single time.
Personality
Sonic is proud, dramatic and absolutely incapable of processing defeat like an adult. His ego is a full-time performance, the name, the poses, the monologues, but the work ethic under it is real: nobody in the series trains harder for a rematch nobody else believes in. He has a strange honour code, a genuine craftsman's respect for skill, and comic timing he would be furious to learn he possesses. Sonic is the rival Saitama never asked for, and the series is better every time he shows up.
Background & Story
Sonic was raised in a hidden ninja village, trained from childhood as an assassin in its Lower Class programme and graduating into mercenary work with absolute confidence in his speed. Hired to eliminate a group of would-be heroes, he meets Saitama, misreads him as one of the targets, attacks at full speed, and is humiliated in a single, physically embarrassing instant. From that day Sonic's life reorganises itself around one goal: defeating Saitama. He trains, upgrades his weapons, declines and then reconsiders monster-cell offers from the Monster Association, and returns for rematches that keep ending the same way, faster, prouder and funnier every time.
Powers & Abilities
- Superhuman Speed: Sonic's speed leaves afterimages and outpaces nearly every hero and monster alive, tenfold shadow clones of pure velocity are among his signature tricks.
- Ninja Arts and Swordsmanship: A village-trained assassin, Sonic combines katana work, shuriken and explosive techniques with acrobatics honed since childhood.
Key Relationships
- Saitama: His obsession, the man who humiliated him, whom Sonic has sworn to defeat and whose indifference is the deepest wound of all.
- Flashy Flash: A fellow graduate of the ninja village system, the polished professional to Sonic's theatrical obsessive, and a benchmark for his speed.
- Genos: Saitama's disciple and Sonic's rival for the position of Saitama's rival, a competition Genos barely acknowledges, to Sonic's fury.
Quick Answers
Who voices Sonic?
Yūki Kaji voices him in Japanese and Erik Kimerer voices him in English.
Why is Sonic obsessed with Saitama?
Sonic's first attack on Saitama ended with Sonic accidentally landing, at full speed, on Saitama's raised fist, in the groin. The humiliation turned a hired job into a lifelong obsession.
