Given his namesake ability to dispatch opponents in a single blow, Saitama, the protagonist of One-Punch Man, doesn't have many recurring antagonists. However, one figure that has persisted to carry out a deep, personal vendetta against the unassuming superhero is Speed-O-Sonic, a lethal ninja who has confronted Saitama on multiple occasions in the manga/anime franchise.

Now, we're taking a closer look at this proud ninja and his powers and abilities to see whether his own moral code makes him an outright villain or a more noble adversary from the anime's colorful supporting cast.

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Who is Speed-O-Sonic?

Speed-O-Sound Sonic is introduced as the private bodyguard of Zeniru, a millionaire living in F-City. When the crime boss Hammerhead and his gang of fanatical minions known as the Paradisers target Zeniru to make a public example of him, Sonic strikes, making quick work of the henchmen as he cuts through them with blinding speed. Wounding Hammerhead, Sonic pursues him through the woods where he encounters Saitama and mistakes him for a Paradiser.

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Running around the bald superhero at top speeds, Sonic attempts to dispatch Saitama with a mighty kick only to accidentally land crotch-first on Saitama's fist, completely incapacitating himself. As Saitama goes off to continue his superhero work, Sonic swears revenge for the epic humiliation, training for an inevitable rematch between the two.

How Powerful is Speed-O-Sonic?

Speed O Sound Sonic One Punch Man

Trained since birth in a remote ninja village, Sonic possesses superhuman dexterity, with most of his movements untraceable by the common eye. While proficient in a variety of ninja weapons and fighting styles, Sonic also has a degree of superhuman strength and endurance despite his relatively small frame, with Fubuki noting that he had abilities and training on par with S-Class Heroes within the Hero Association.

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True to his name, Sonic can move at hypersonic speeds when he focuses and use this ability to create the optical illusion that there are multiple copies of himself at once. Initially, Sonic is able to produce four after-images of himself but, after intensive training to gain revenge on Saitama, has since upgraded the ability to generate up to ten after-images.

Hero or Villain?

While Sonic has an avowed grudge against Saitama, he also quickly realized that his rival was a genuine hero, and sought to force a confrontation between them rather than simply attack him in the midst of his usual heroic deeds. Saitama's friend and protege Genos would fight Sonic to defend his mentor's honor, with the two figures battling on relatively equal footing. Despite this longstanding rivalry, however, Sonic would reveal himself as a clear opponent of outright evil.

In Season 1, Sonic fought against the monstrous Deep Sea King, initially putting up a good fight until the creature steadily gained power due to his exposure to water. Barely escaping with his life, Sonic would warn Genos about that the danger that the monster posed. While dismissing an offer to join the Hero Association to focus his efforts on defeating Saitama, Sonic would contemplate an offer from his two former associates to eat monster cells to augment his power and join the Monster Association. Feeling that the increase would give him an edge, Sonic cooked the monster cells rather than eat them raw which resulted in severe diarrhea instead of triggering a monstrous transformation. Later, Sonic would appear to join a plot to kill his former master only to turn on the attackers and enduring a change of heart and adherence to his own ninja code rather than resort to betrayal.

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