Huehuecoyotl, known as the "God of Calamity," keeps showing up around Arata—mostly because Arata reminds him of someone from his past, a guy named Seimei. The similarities are pretty striking: same look, same kind of powers. Sometimes Huehuecoyotl just calls him Seimei out of habit or amusement.
Personality-wise, he's generally easy to get along with, but don't count on him to care much about how his actions affect regular people. True chaotic neutral—he does what he wants, and human feelings aren't really on his radar.
Content compiled by AnimeList.moe from publicly available sources.