Board Thread:General Discussion/@comment-122.62.95.49-20151128041147/@comment-4010415-20151128043332

I'm pretty sure it's Theory #3. In Burning the Candle, Yang called him "our uncle". OUR. Not "Ruby's". OUR. Meaning that she and Ruby both consider Qrow to be their uncle, even though he is only Yang's uncle.

And we know that he's only Yang's uncle because Raven Branwen is Yang's real mother, as evidenced by the fact that Yang said Summer, Taiyang, her real mother, and Qrow were on a team together, and the Volume 3 Opening features an old photograph of Summer, Taiyang, Raven, and Qrow standing together as a team.