Board Thread:Episode Discussion/@comment-27366857-20151208163511/@comment-4010415-20151208164002

I... What? No. Ruby and Yang are half-sisters. Qrow is not actually related to Ruby, at all. She just calls him her uncle because that's what Yang always called him when they were growing up.

Qrow is Raven's brother, and Raven is Yang's mother.

We know for certain that Raven is Yang's mother, thanks to the photo of Team STRQ. In Burning the Candle, Yang said that Summer, Taiyang, her real mother, and Qrow were on a team together. The photo of Team STRQ shows Summer, Taiyang, Raven, and Qrow. Therefore, Raven is Yang's real mother.