Board Thread:Speculation House/@comment-4830106-20131110184853/@comment-15838853-20131122072153

Maki Kuronami wrote: There was never any mention of Cinder's full name until Monty posted it in facebook. Cinder was only called "Cinder" in the credits of episode 16.

Then a random "montyoum" showed up and revealed her surname, alongside Qrow's, which is apparently Branwen.

That's the thing we need to be revealed. If Qrow's surname is really Branwen, then we don't need to ponder if the Monty that showed up in the wikia is fake or not.

http://rwby.wikia.com/wiki/Thread:76401

We actually got Cinder's last name from Monty's facebook