So here's what I think about the personalities of the 3 void dogs.

Qualm: Smart, bad sense of humor.

Omen: Bloodthirsty, aggressive.

Gevaar: Crazy/Insane.

Is it accurate?

For your concept art of the 3, you should use the alternate skins for Omen on http://leagueoflegends.wikia.com/wiki/Omen for ideas but change them to make the 3 different from each other, but keep them from looking too different.

are you done with the concepts yet?

I've had a lot going on so i didnt get to my drawing desk for the past few days, working on them today. Ill have something up by the end of today.

Concept 1/3 is added, the shown Voidbeast is Qualm. I'm still working on the other two, once I have a solid idea of what they all look like I'll add in one that has all 3 of them together.

EDIT: I'm beginning to strongly favor the idea of the "Hextech Swarm" for his release skin. Something about that seems to work the best out of everything so far. Let me know what you think of this or any other skin ideas that might be cool.

EDIT: I have officially decided, the starting skin for the Swarm will be the Battle Cast Swarm, having seen the speculation of Battle Cast Cho'gath and Battle Cast Skarner. Upon completion of Gevaar, and Rolepeek's minions, I will do concepts for the Battle Cast Swarm.

what color are each of the void dogs?

to keep with the overall theme they would be more of a purple color but I do believe I would have it more of a red-purple/magenta color rather than an indigo/blue-violet color.

(Btw, this is Mount, I had a name change.)

EDIT: The void dogs will be as as follows:Magenta Omen : Deep Purple Qualm : Indigo Gevaar

Omen Concept added.