This is Firhaur

Firhaur is Gaster's predecessor as Royal Scientist. He's a pretty big character in A Name to Remember.

But anyway, for some other information about him-
-he walks on his wings, but if he needs to run, he does that with his hands
-he can fly with those wings, too
-he breathes purple fire
-Perseverance is his main Soul trait
-he doesn't wear a lab coat because his scales would protect him in the event of a chemical spill or whatever. The fact that he doesn't wear a lab coat annoys Gaster to no end--... for reasons I'm not going to spoil here.
-he's about 10 feet tall (top of his head, not top of his horns)
-there's more stuff, but eh, we'll save that for the actual story.