Who Really Attacked Kaer Morhen Before The Events Of The Witcher?
The title of Netflix's epic fantasy series "The Witcher" refers to a type of monster hunter, gifted with magical techniques inaccessible to humankind at large. One of the show's three protagonists, Geralt of Rivia (Henry Cavill), is the Witcher referenced in its title, and his enhanced strength regularly lands him in perilous, supernatural conflicts, fueling much of the series' ongoing drama from episode to episode.
Whereas Geralt's past prior to becoming a Witcher is largely unexplored in the first season of "The Witcher," early on in Season 2, Geralt returns to Kaer Morhen, the Witchers' stronghold. It's there that Geralt, and virtually every other Witcher in the series' fictional world, transformed from a regular human being into a supernatural monster hunter. That said, the Kaer Morhen in the present of "The Witcher" is markedly different than that of its past. The reason Kaer Morhen is in something of a compromised state when Geralt returns there with his adoptive daughter Ciri (Freya Allan) in tow is due to an attack on the stronghold detailed in the climax of the "Witcher" tie-in film "Nightmare of the Wolf" released on Netflix just months before the mainline series' Season 2 premiere.
A mage named Tetra led the attack on Kaer Morhen
The two principal characters in animated "Witcher" prequel "Nightmare of the Wolf" are Geralt's mentor Vesemir (voiced by Theo James) and a mage named Tetra Gilcrest (Lara Pulver). At one point in the film, Tetra reveals that she has held significant contempt for all Witchers since her mother was killed as part of a Witcher's scam when she was a child.
During the events chronicled in the film's present, she discovers that elder Witcher Deglan (Graham McTavish) is creating monsters and setting them loose in the world in order to drum up new business for financially struggling Witchers. This, in combination with her general distrust for Witcher-kind, compels her to lead an attack on Kaer Morhen alongside the transmogrified elf Kitsu (Kari Wahlgren). Together they use their powers to lead a huge army of monsters into the stronghold, alongside a mob of similarly angry humans.
Though Tetra dies, meaning that Vesemir technically comes out victorious, her attack takes the lives of virtually everyone but the youngest Witcher candidates. By the film's end, then, Vesemir has to rebuild Kaer Morhen's population more-or-less from scratch following their costly battle.