Board Thread:News and Announcements/@comment-26564088-20190924213811/@comment-29684190-20190925004558

Ok, so I did some digging and at Connichi 2017 MILES LUNA said that Cinder's Semblance is dust (as in normal dust, not Dust) manipulation.

"...and can turn it into glass and stuff (because of Cinderella's glass shoes). When she killed Pyrrha, she decided to go a bit overboard with her new powers. Pyrrah was incinerated from the inside out. It was also decided to be shown on-screen so there wouldn't be any theories like "oh she just survived". But then, they said, there were theories like "she just got teleported away!" which pretty much was the opposite of what they intended to say. "

So yeah. Unless I am mistaken, Miles Luna is yes, a voice actor, but also a writer for RWBY.