"Speed-o'-Sound Sonic is a highly skilled assassin and one of the primary antagonists in the One Punch Man anime. He is known for his incredible speed, agility, and his titular sonic-based attacks.

Originally a member of the ninja village of Iga, Sonic left his home after growing bored of his ninja duties. He then began working as a freelance assassin, taking on various jobs across the world.

Sonic's main goal is to prove himself as the strongest warrior in the world. He sees himself as superior to all others and takes any opportunity to show off his skills. This arrogance often leads to him underestimating his opponents, which has resulted in him getting defeated multiple times.

Despite his somewhat egotistical personality, Sonic displays a strong sense of honor and will not hesitate to help those in need if it aligns with his own interests. He is also a skilled strategist, able to quickly analyze situations and come up with a plan of attack.

In battle, Sonic's speed is unmatched. He can move at supersonic speeds, and his attacks are based on using sound waves to create powerful sonic booms. He also uses a variety of weapons, including shurikens and high-tech gadgets.

While Sonic is a formidable opponent, he is not invincible. He has been defeated multiple times by the strength of his opponents, including Saitama, the protagonist of the series.

Despite his losses, Sonic remains determined to prove himself as the strongest warrior. He continues to hone his skills and seek out new challenges, always looking to push himself to the limit."