^^ Funny I've always seen Rex as a dog's name, but I think it fits your character nicely. Also great combination of colors; the tones compliment each other fairly well. I would lighten the color of the mane a titch so it blends with the pelt's tone a little better (I dunno maybe it's fine the way it is but try it out and see how he looks :L) but that's up to you. Either way your lion looks great. ^^
