User blog comment:TheBlueRogue/The Witcher 3 "The Trail" Fannotation Trailer/@comment-155.158.57.124-20141029152640

The raven is most likely a one-time use amulet CD Project Red came up with, similar to what Ciri used in Vengerberg in the 1st tome (except that one made her invisible). The only magic birds Sapkowski wrote about was the owl Philippa turned to and two kestrels created by Yennefer in the Sword of Destiny. The only raven mentioned in the saga is Vysogota from Corvo, an old hermit that stitches Ciri's cheek wound.

Yennefer's star is a very advanced artefact that should allow her to cast magic without sapping into a source (a chosen element; earth in the trailer). It's more than just a magical item, it allows her to become one with the Magic, acting more like a transistor. I guess her having amnesia explains it not working properly. It should be much bigger, however. In the books there are several fragments saying she was playing with the star by rotating it in her hand and such. I guess it could be a makeshift item made in place of the old star but it doesn't really make sense - it would require an awful lot of money to make it (which is hard to come by if you're a witch in Nilfgaardian territory), not to mention she had a connection to the original star.