Board Thread:Speculation House/@comment-114.79.60.17-20160626164308/@comment-4010415-20170125143910

179.25.150.174 wrote: I think I found a small hint of what his semblance is in the merc em vs Coco and samuri dude right after the brakedancing kick tornado of dust #TheBestMoveEver you can see Mercury apier behind Coco and that samuri dude who's name I can't remember if you slow it down you can see his hair move making it look like he used some sort of super speed that's all I've got

Probably not. Ruby's Semblance was stated to be speed, and it was stated that Qrow and Winter flashing around during their fight was literally what the students who watched were seeing because of Qrow and Winter's skills as full-fledged Huntsmen. From that, we can conclude that Mercury has a high enough amount of skill to move incredibly quickly, just like Qrow, Winter, and Tyrian.