Whirlpool: One Punch Man

Indigo, a boy with hydrokinesis, moved to City Z, unprepared to meet his new neighbor; who turned out to be quite the extraordinary person from his past.
The chance to become a professional hero reared its head, and the blunette of course took it. With his friends, he may not have the advantage of power, but his ability has its own advantages.

Although... he may have more than one demon from his past to work on at the same time. And drowning your problems isn't as practical as it sounds...