Speed-o'-Sound Sonic, often referred to simply as Sonic, is a recurring character in *One Punch Man* known for his incredible speed and ninja-like abilities. He is a self-proclaimed rival of Saitama, though their encounters are hilariously one-sided, as Sonic's extraordinary speed and skill are still no match for Saitama's overwhelming power. Despite being a human, Sonic's agility and reflexes allow him to move at blinding speeds, outpacing most heroes and monsters in the series.
Sonic comes from a background of elite ninja training and possesses a wide array of deadly techniques, including his signature "Ten Shadows Burial," which uses high-speed movements to attack his opponents with precision. His obsession with defeating Saitama becomes a defining part of his character, as every attempt to challenge him ends in humiliating defeat, often in comedic ways, like when he accidentally hurts himself due to Saitama's nonchalant counters.
Despite these repeated failures, Sonic remains determined and resilient, constantly training to surpass his limits. He is a loner, with a cold and serious demeanor, viewing himself as a superior fighter who operates outside the hero or villain systems. His rivalry with Saitama, though mostly one-sided, adds humor and excitement to the series, showcasing the gap between Saitama's strength and other powerful combatants.
Sonic’s design and fighting style are sleek and deadly, with his mastery of ninja techniques making him a formidable foe against most enemies, though his pride often gets in his way. His interactions with other characters, especially Saitama, bring a blend of action, rivalry, and comedy to *One Punch Man*, making Sonic a fan-favorite anti-hero in the series.