Sunomono is a tiefling of mine for 5e, themed after Oni of Japanese folklore.

He's a warlock whose patron is a oversized frog spirit whose tongue is riddled with faces (thus the name Ganmen, which translates directly to that). Ganmen is a spirit of ill-gotten fortune, and often guards his touch of good luck with spiteful conviction. When he does interfere with Suno's life, it's to teach people the dangers of generosity, whether it be from a stranger or friend notwithstanding.