Board Thread:General Discussion/@comment-26281589-20131112205848/@comment-26018514-20150515050230

Raven is almost definitely related to Qrow, this indicates either Sister, spouse, or progeny. We have no indication he has either of the last 2, what we do have is evidence that Qrow's Sister was on Yang and Ruby's parents team of 4, which consisted of Qrow, Summer, Tai-Yang, and Yang's mom.

Given that neither Ruby nor Yang talked about a cousin or aunt, yet Raven at least knows Yang, It can be inferred from almost every angle that she is Yang's mother.