Skin Concept- Demon Vel'koz
Not really an artist, but I drew what I could of a rough sketch of the base + abilities: http://imgur.com/bqCePNg&sn8VaMn
-Basically imagine Vel'koz but with an eye resembling that of sauron from LOTR and with armored devil-like horns extending back and curving at the tips on each side and on top. The tentacles would be red with a black scaly texture and maybe even with a demon tip on his back tentacle.
Abilities:
Passive: Instead of the little triangles, there would be 3 little fireballs and when they're researched, the circle that appears could have a pentagram symbol as well.
Q: Shoots a red blazing fireball. Fiery detonation effects on activation as well as an image of a green skull/spooky face in detonation explosion. Smaller Fireballs shoot outwards from the skull face. Maybe the initial fireball has a "eyes" on it as well, so like a fiery ghost ball.
W: Opens a portal to hell. Edges of the portal are black and resemble a gate with archaic symbols, while the interior is a fiery whirlpool. Fiery effects upon detonation or even ghost effects flying up.
E: Pentagram. Green outline of a pentagon surrounded by archaic symbols on the circumference of the circle. Detonates in a red/orange fiery explosion.
R: Firebeam. The laser should try to resemble fire as best as possible and have some kind of fiery crackling effect in the visuals and sound.
-For the abilities I was thinking a ghostly green color for all of the pentagram/symbol lines and a fiery red color for most of the other effects. Also the skin would ideally be of legendary quality or at least 1350 level.
Bonus: A common Vel'koz combo is E followed up by a quick W, so with this skin it would look really cool as your portal to hell will be "opened" by the pentagram symbol from the E.