Traces are, in general, not accepted here -- you have a much better chance of getting your art approved if you didn't draw it directly from the game. Furthermore, it is beyond all doubt or question that posting actual official art from the game on deviantART is an infringement of copyright. Spitting out some boilerplate copyright information in the description (© LAB ZERO GAMES HERP DERP I OWN NOTHING) is not sufficient to protect you from accusations of art theft.
and other Lab Zero personnel are the only exceptions to this rule, as they are the actual owners of the art in question.
I don't like being a stick in the mud about these things, but judging from what I've seen on this site in the last couple of days, it apparently needed to be said -- not just in relation to Skullgirls, but to pretty much everything you can search for.