Board Thread:Off Topic/@comment-25396609-20150826013454/@comment-26397825-20150827031312

I'll be honest, I thought Vayne referred to Vein, as in the veins in your arms, which appear blue when under the skin and the blood that comes out of them is red.

The 'limit to one thing' stems form the fact that so far, no canon semblance has been shown being able to more than one thing without creative application of the semblance itself and dust interaction. Weiss's semblance, before you pount out its versatility, is widely regarded as the ability to either 'push and pull' something, and then she just uses dust to create other effects, OR the ability to bring out the metaphorical abilities of dust (such as speed for lightning dust, instead of just a lightning attack, the pull effect from gravity dust, the 'rises' or push effect from heat created by fire dust) alonside just plain making elemental attacks, which any Dust Mage can do.

So while electromancy itself is a good power, there's just way too many different things that you can do with it to count as a viable semblance because they are so different that you can't really link them to each other as creative thinking, and really are separate abilities lumped underneath one name.