Qrow Branwen

Crow is a currently-unseen character in RWBY and Ruby's teacher at Signal Academy, as well as her uncle. He was mentioned in the first episode as being the one who taught ​Ruby how to fight and wield her High Caliber Sniper Scythe, Crescent Rose. Professor Ozpin seems to know him, and figured Crow was the source of Ruby's training since she was apparently as good as he is during her first fight of the series. He is as good of a scythe wielder as Ruby.

Trivia

 * Due to the exact unknown relationship between Ruby and Yang Xiao Long, it is unknown if Crow is also Yang's uncle.
 * The name and (possibly overall) character of Crow is likely a reference to Monty Oum, who commonly adds a crow in his works as a kind of signature. Even in RWBY, a crow has appeared in the "Black", "Trailer Red" and "Yellow" Trailers before the character of that promo went into action.
 * Due to the number of other characters who appeared in the Pilot episode that are seemingly influenced by the 1900 novel The Wonderful Wizard of Oz and its 1939 musical film adaption, such as Ozpin and Glynda Goodwitch, fans have speculated that Crow will allude to the character Scarecrow.
 * The mumbling of the phrase "That's my uncle!" by "(Ruby) Rose" is possibly a refrence to the Rooster Teeth Animated Adventure Left 4 Trek.