Werewolf, or a Lycan. Lycanthropy was considered a real disease in ancient times where a bite from a wolf resulted in becoming a monster that would change from a human to a werewolf during the full moon.
There are a lot worse things in life than being headquartered at Kaer Morhen. It has gorgeous views, great training grounds, and is home to the greatest monster hunters alive. Show your allegiance to the Wolf School, Witcher!