Akuma-kun(1989)

Akuma-kun is a supernatural series about a young boy thrust into an ancient war against demons. When the dying Dr. Faust discovers that Shingo Yamada bears a mystical birthmark marking him as humanity's chosen protector, he summons Mephisto, a reluctant devil from hell, to aid the teenager. Bound by a blood pact, Shingo and the sardonic Mephisto form an unlikely partnership to combat the rising tide of evil threatening Earth. The series blends action and dark comedy as the mismatched pair navigate the supernatural underworld, with Mephisto's cynicism clashing against Shingo's determination. Together they must master demon-fighting while uncovering the truth behind the prophesied age of demons and Shingo's destined role in stopping it.