A well-known example comes no earlier than the first episode. Souichiro deliberately takes advantage of Masataka's feelings for Aya during their fight in the cafeteria, hoping that it will give him an edge in the fight. This happens instead.
Not only does Masataka impress in the beginning of the series but middle and end. Hell throughout the series.
After Madoka Mawari gets back up and impales Emi with her laser blade and wrecking Bob's hair and severely injuring him with said blades Masataka does a Big Damn Heroes and does a palm blast through Bob's chest which does shoots back Madoka to the wall. Because Bob was given such a brutal beating Masataka says "This is the first I've been angry for the first time in a long time". Next chapter: cue fight ending in a single strike from Masataka. I repeat: One hit.
Not even a day later Masataka gets into another fight; this time with an undead Fu Chien. After getting his ass handed to him not too long ago he goes to Bunshichi's store to ask for help. Even though Bunshichi lends him help it's Masataka who does the most fighting and is able to avoid being shocked by his Earth ki (electrical powers) by sliding his foot under Fu's which prevent him from making contact with the ground and thus being shocked.
The most amazing feat performed by Masataka in that fight however is that he stopped Fu Chi'en from launching an electric blast that would vaporize everyone in the area. By striking Fu Chi'en so hard that the amulet which possessed him is destroyed he was able to stop Fu Chi'en and saving everyone in the area. Sohaku who cast spell to revive Fu Chi'en as a zombie is bleeding as a result of the spell being undone and Fu Chi'en being no longer under his control. Because of this Sohaku believes that Masataka may be the closest to becoming the True Warrior
On another note favorite character for this troper who established himself as badass is Bob Makihara. Near the end of the manga in a chapter which is a timeskip. Bob has a rematch with Madoka Mawari which he is shown to finally become attuned to his Rhythm power which allows him to utilize his Capoeira martial arts skills by listening to the vibrations in the ground and predict an opponents movement.
In another chapter Bob is seen arriving to the Juuken club running 20KM in 1:10 flat. 20KM in 1:10 FLAT. 0_0
A team one with Soichiro, Maya, and Mistuomi. The three of them are pinned down by four girls wielding shoulder-mounted machine guns, flame swords and blades. Each. And using them through neural links via their fingertips. The response to the onslaught is a Forged Iron Needle Punch, the first move Soichiro learned. He and Maya throw one, but Mitsuomi, never to be outdone, uses the rotation of his shoulders and arm to throw TWO for a combined four-part explosion.