My entry for the 2006 Blizzard Fan Art Contest.
I wanted to create a character that someone *could* potentially have in the game--that is, wearing armor that's currently available, etc. To add a bit of humor, at least for people who have played the game, I decided to make the armor relatively mis-matched as it nearly always is. Thus, he's wearing Dreamwalker, Stormrage, and the Marshal's Dragonhide Legguards. (And yes, that's a level 34 Yeti Fur Cloak...just for kicks...hehe.) Pardon me while I geek out.
Anyway, I don't believe there's a demon quite like this in the game right now, but...I just wanted him to look neat, with lava veins and all. (Maybe they'll make one? :D )
I spent almost enough hours on this to have leveled up this character and gotten this armor for myself. Almost.

Sketched on paper, painted in Photoshop and Painter.