Moguro is some kind of yokai.
Many yokai have strange supernatural abilities and many can pass themselves off as human. Moguro certainly looks human, but he's able to do things no ordinary human can. Moguro is a demon who sincerely wants to help people.
The problem is his innately evil nature always ends up showing itself, screwing over his clients. He is fully aware of this and is in despair over it, but he always tries to hide this with his signature smile and laugh. Moguro was, in an earlier form, the fabled 'person on business from Porlock' who ruined the poem Kubla Khan.
Depending on whether or not he's actually trying to do good, he considers it either his greatest failure or greatest victory. He memorializes it by waving a circle round him thrice
. Moguro is a tanuki/bake-danuki.
Throughout several episodes, a tanuki is either referenced or plays some role. In one episode, a tanuki statue is used to lose weight, in another Moguro remarks how modern electronics can trick you like one and in one episode there is a big tanuki statue outside a shop - Moguro calls out to a customer and once they come to him, they find the statue where Moguro was presumably standing. Heck, in one episode where one character consumes some psychoactive mushrooms, Moguro even assumes the shape of an anthropomorphic tanuki. Not only that, but he is also a trickster character that physically resembles an archetypal tanuki. The bartender is a client.
Specifically he requested to be allowed to truly understand humanity, its heights and depths. Moguro granted that request with the proviso that he say not one word to influence the outcomes of Moguro's deals.