Board Thread:Speculation House/@comment-108.69.217.22-20160216061533/@comment-26397825-20160216203832

As confirmed by Monty himself, Yang and Ruby are half sisters. They share the same father. Summer is Ruby's mum. Raven is Yang's mum. We were told this outright in the series and by many many people who work on the show, including Monty.

Qrow is just the drunk but awesome uncle to both girls. He's not even related to Ruby by blood. She just calls him uncle because she loves him like one.