Zetman

There are two forces in the world: the Zet, who are entrusted with the survival of humanity, and the Alphas, who have chosen an extreme form of justice. In a certain city, Jin lives under a bridge with an old man, struggling to pay off debts. He carries the destiny of humanity's survival. Kouga lives on a hill and stands to inherit vast wealth. In his admiration for heroes, he seeks out the meaning of justice. They don't know it now, but they are destined to one day meet.

Synopsis from Anime News Network