Shworunner Lauren Schmidt Hissrich is a pretty active twitter user and she recently revealed a list of characters that will appear in The Witcher. One of them was Vesemir, the oldest and most experienced witcher at Kaer Morhen (basically a hardcore version of Hagwarts) and a father figure to Geralt, the main hero. Vesmir was also the only one of the witchers who survived the assault on Kaer Morhen.
One of the series fans responded to Hissrich and tagged Mark Hamill saying that the actor known for his work on the Star Wars saga and Batman: The Animated Series, should get the role. Quite surprisingly, Hamill seems to be fond of playing Vesemir, even though he has no idea who the character is. But you should definitely cool your jets, as the casting for The Witcher hasn't even started yet.
Hamill also recently revealed that he would love to play Doctor Octopus in a Spider-Man: Homecoming sequel or a cosmic being in James Gunn's Guardians of the Galaxy Vol. 3. After The Last Jedi, it is understandable why he needs to find a new job and let's hope Hamill will find a new home in Kaer Morhen or the Marvel Cinematic Universe. May the Force be with you, Mark.