Henry Cavill as Geralt of Rivia, a witcher or monster-hunter.
Anya Chalotra as Yennefer of Vengerberg, a powerful sorceress.
Freya Allan as Princess Cirilla (or Ciri) of Cintra.
For those asking, in the books Geralt only carries one sword on his back. His silver sword, used for fighting monsters, is kept on his horse, Roach.
Netflix's The Witcher is tentatively scheduled to air later this year, possibly around November.