Hirotaka

All info provided http://kimpossible.wikia.com/wiki/Hirotaka

Hirotaka is a top student from the Yamanouchi Ninja School in Japan, he and Ron switched to each others' school in an exchange program. Upon arriving to Middleton, he gained the attention of every teenage girl there. He seemed interested in Kim mostly for her martial arts skills. He seems to be very aware of the attention he gets from the ladies, but doesn't seem to care, and appeared to have been dating Bonnie the whole time.

In terms of skill, Hirotaka seems to be one of Yamanouchi's more advanced students and possesses a great deal of stamina through his training. When he asked Kim to demonstrate her skills to him, although neither of them actually hit the other, Hirotaka was shown to have been somewhat faster than Kim when fighting her, and in the end Kim was left winded, while Hirotaka hadn't even broken a sweat. He also seems to prefer a more defensive style of combat, not fighting back unless he absolutely has to. When Brick tried to pick a fight with him at Bueno Nacho (because of Brick being angered at the attention Hirotaka was getting from all the girls), Hirotaka was perfectly happy to simply evade Brick's attacks and let him exhaust himself to the point where Brick couldn't fight anymore.