I like concept of this one...
One thing I noticed. The pillars behind the mage need to be lit up since the crystal is giving off so much light.
Also your mage should have some sort of shadow cast from that brightness in front of him no?
I kind of over did the brightening up of the pillars to show you... since I was working mostly with black, I didn't want to have to re-do it with all the detail that should be there. IF you saved an original pillar layer, before you darkened them, then this should be an easy fix.
Think of a bright light on the floor in the middle of a room. Would the walls be black surrounding it? Or would they be lit up by the light source?
You could always take a lamp and place it in the middle of your bedroom, remove the shade and see for yourself.
I also used a photo filter (cooling filter 82) set at 25% and then used a mask to only have it in the room, and not affecting the nature outside. This gave anything highlighted in the room a blue tint. The mage, the walls, the floor... Instead of the white you had. I did this because your light source is a blue crystal. Had it been red or yellow, I would have used those tints for my photo filter. Its a little step that not a lot of people do, but it brings all of your different sources together nicely using color correction.