Gouketsu

Gouketsu is a major antagonist from the manga/anime series, One Punch Man. He was once a martial artist and the first champion of the Super Fight Tournament. He later challenged Orochi to a battle, but was quickly defeated and was given a choice; join the Monster Association or die. He serves as one of the main antagonists in the Super Fight Arc.

Appearance
When Gouketsu was a human, he was a muscular man with spiky, dark hair and a black karate uniform. He also had a scar on the side of his upper lip.

When he became a monster, he grew four sharp-looking eyes, sharp teeth and spikes across his entire body. His scar also seems to have disappeared and has instead been replaced with a large X-shaped one instead at the bottom of his face.

Personality
Despite his terrifying appearance, Gouketsu is a calm, intelligent being, knowing his limits and keeping his arrogance in check. He is still an arrogant being, however. He treats other martial artists as lower classes compared to him and states that becoming monsters will turn them into better fighters.

Nonetheless, he is aware that there are other monsters that are above him, as he uses this reasoning to rationalize with Bakuzan, who attempted to beat him after becoming a monster. He's also shown to connect with others, as he understood Bakuzan's feeling when he transformed into a monster.

History
To be added.

Powers and Abilities
When he was a human, Gouketsu had one the first Super Fight Tournament and became the first champion. He believed in himself that he could take on the Monster King himself with his abilities.

As he transformed into a monster, his power and abilities have been augmented to an immense degree that labels him a Dragon Level Threat. He has taken out Genos and Suiryu with ease and effortlessly took on Bakuzan after he became a monster as well.
 * Superhuman Strength: Gouketsu is insanely strong. A single punch caused a shockwave that destroyed a large portion of the Super Fight Tournament stadium. He was also able to gravely injure Genos and smash him into the ground. He was also able smash Suiryu into the ground with a single punch and break his left arm.
 * Superhuman Speed and Reflexes: Despite his massive size, Gouketsu is extremely fast. He was able to casually block all of Bakuzan's swings with just one arm and was even able to stomp down Suiryu before he could even react. He was also able to one shot Genos before Genos could even react as well. Gouketsu was also able to watch the clash between Suiryu and Choze, who were moving at impressive speed.
 * Superhuman Durability: Gouketsu was able to tank hard blows that were sent into his eyes from Suiryu without having the need to even block his attacks. Bakuzan's punches also meant very little to him when he casually blocked them.

Trivia

 * When Yusuke Murata initially drew Gouketsu, he had a slightly different design for him that made him look more monstrous. The reason he changed the design is because he wanted him to look more intelligent and calculating by giving him a less threatening design, using Frieza's final form as a comparison.
 * Additionally, Gouketsu bears somewhat of a resemblance to Goku, both wearing a martial artist outfit and have spiky dark hair.