User blog comment:RWBY Ruby Rose/Semblance Concept/@comment-8182065-20131217204213

Okay with Semblances, I don't think there's much to go on for us on the Fanon. The only known rule to me, besides the fact that they can't be OP, is that they cannot be the same as characters in canon (so no actual speed, or actual polarity).

Right now, coming up with one is a great difficulty, because they have to be unique, yet stick to what we know from canon without having a Semblance that's the same as a character's from canon. Glyphs, however, are the easiest as we have 3 characters who use them in Canon, because they all have different functions as well as appearances, but we all can't have glyphs (it might not fit with certain characters plus it'd be boring :P). And there is the option of keeping them unknown until we learn more about the topic.

Uhm, can we get a v 1.0 guide on Semblances?