Umbra

He's a friendly bean and lives in the same part of hell/purgatory that Imp was created in => they have met before and became friends

rn I'm toying with the idea that Umbra is actually a fallen angel, making him quite the powerful demon... but he doesn't know. He accidentally 'fell' from heaven by getting roped into a bigger scheme and lost his memory during the transformation from angel to demon, leaving him stuck in his cute hell-ish creature form - until he slowly started to figure out his powers again. That probably happened with the help of another demon who took him in and helped him get the hang of shape-shifting back into his humanoid form.

The garment he's wearing resembles his previous clothing as an angel, but it's darker and has some practical adjustments regarding his tail and the crystals on his hips.