"I won't forgive you" is such a lame line to say to an enemy. Who cares if my enemy "forgives" me? They aren't my friend to begin with. Why do Japanese manga authors (and maybe Japanese people in general?) think that phrase sounds at all threatening?
They trained in the Himalayas, then they decided to go to a random Japan theme park?
In any case, a debuffer and a slow but powerful attacker is a very dangerous combo. But it seems Kiyomaro is waiting for somebody, so maybe an ally will come.