That picture is a really good choice, but I wonder if the transition from the dark/blue palette to the lighter palette of the main menu you posted a while ago (on the old forum with the animated menu iirc) will be jarring. I agree that this isn't really a big deal, but I do think it makes sense to have a theme that is consistent throughout.
The Realm Lobby gui looks really good. I was going to suggest changing the button color to blue, since the pictures and the border have a blue palette, but I think it works because the picture on the right actually gets darker and red at the bottom along with the demon symbol with the red eyes in the middle. Pretty interesting actually.
By the way, I hope the gem can be activated still.
