The Raven is a minor character in Snow White and the Seven Dwarfs. His purpose in the film is as someone for the Evil Queen to speak to (mostly as the Witch) in order for plot points to be conveyed to the audience. He appears to be intimidated by the Queen, in both of her forms.
Role in the film
The raven seems to live in the Evil Queen's laboratory in the dungeon. When first seen, he is sleeping, perched on a skull; he wakes when she enters, and is startled by the effects of the ingredients of her potion. He is frightened by the Queen in her Witch form, and hides in the skull, peering out of its sockets. He watches the Witch preparing the Poisoned Apple, and as such is terrified when she, as a cruel joke, offers him the apple. The Raven is not seen after the Witch leaves the castle, leaving his fate uncertain.
He may have been an inspiration for Diablo, from Sleeping Beauty. Both are ravens and have similar curiosity and intelligence.
The Raven appears in Once Upon a Time season 6, when Regina delivers a false message to distract Zelena for that she surprise the Evil Queen and Gold in intimate relation, while Emma, her parents, Hook and Blue search a way to trap the Evil Queen.
Behind the scenes
The raven is one of several characters used to interact with the Queen to add conviction to her character. Joe Grant knew the work of Wilhelm Busch, and it is likely that he was inspired by an 1894 Busch illustration of a raven perched on a skull.
Stirring the Cauldron
A very short sequence involving the Witch stirring her cauldron was fully animated and completed, and was among the scenes cut from the film by Walt Disney at the last minute. In the sequence, the raven looks on as the Witch stirs the cauldron with a huge bone. She pauses to see that the smoke rising from the brew is shaped like skulls, and adds a drop of an unknown ingredient to the concoction:
"Boil, cauldron, boil. Boil, cauldron, boil. Death within thy depths I see, for one who dares to rival me. Brew the magic recipe, boil, cauldron, BOIL!."
At this, smoke from the cauldron fills the room. This sequence would have occurred immediately after the scene of the Seven Dwarfs going to sleep in their cottage; the sequence would have been followed by the scene in which the Witch dips the apple into the brew to make it poisonous.