The detail of the Lich King from his skull to his armor, crown, and staff to his withered robe is breathtaking. I love the blue glow you gave him, so it looks like he's emanating power. Lastly, I love the dark and suspenseful mood the skulls on the ground create.
Also, this piece of art reminds me of the King of the Skull Servants card from Yu-Gi-Oh. I noticed in your Author's Comments that you did this for a card game. Not sure if that card inspired you, but that's what it reminded me of. Superb work nonetheless!