Manga with a prodigal martial artist whose body is limited to half power by his father
This is Aiki.

Kunitoshi Joukyuu is a lazy ass, good for nothing pervert. Who also happens to be a supposed genius master of Aikido, the strongest in the world, if not because his father sealed away most of his abilities before dying.
So now he's stuck trying to find a way to rid himself of the &quot;curse&quot; that had been put on him all the while getting involved in fights with beautiful high-school girls who are a part of a power-struggle over a school.
But none ever suspected the true sadistic monster that hides underneath the calm and bored face he usually wears.
Who will be in greater trouble? The girls, or Joukyuu?