[@Gentlemanvaultboy]
Well, my verdict's going to be a bit weird, so bear with me for a bit ^^;

As far as Mephisto goes, I never gave a description and I never settled for one either because his appearance hasn't been so important, and I don't feel like it'd be that important either. What you've got for Mephisto would obviously suit him, but in general I picture Mephisto being a bit less serious than most of the pictures there. He's big and dangerous, but he because he's big and dangerous he doesn't have to care about anything he doesn't feel like, so he's always been a bit whimsical but purposefully so.

As far as Alto goes, I also never figured it'd be too important because you'd probably be blind most of the time while you were fighting him. I am partial to your choice, but it sort of feels like long hair would be a pain to deal with while fighting people.

King I described as being kind of normal like, so think like the 'normal' male main character of any given high-school anime, and make them a bit more normal and maybe give them a haircut before putting King's clothes on him.

And as for Clara, all I had pinned down were long hair and red eyes, but those'd be optional I think? ¯\_(ツ)_/¯ Anyway, her height is sort of significant to me though. She'd be taller than Bak, but she'd be about even with Alto I'd imagine, maybe slightly taller.