Shouhei Inagaki

Inagaki was the National high-school champ.

In the anime he decided to spar with Joe because he went into their gym without permission and was being rude, Joe ''lost'' the spar and immediately started disliking Inagaki since he was acting arrogant and was making fun of Joe.

They later meet each other again while Joe was taking the pro-test where Inagaki once again was teasing Joe and acting arrogant. (This is where they meet for the first time in the manga)

Later on during the test they were picked to spar against each other with the fight being for the most part one-sided on Inagaki's behalf. Joe gets more and more frustrated and later on uses his famous ''no-guard'' stance for the first time which throws Inagaki off guard so he misses.

Joe then starts to hit Inagaki with all he got until he is hit outside of the ring where Joe then chases after him outside of the ring beating him up so hard that he almost thinks he had killed him.