Season four begins with an ambush from the Gutter Rebellion, and hard choices needing to be made.
The Witcher novels are written by Andrzej Sapkowski: https://www.hachettebookgroup.com/series-list/andrzej-sapkowski-witcher-books-in-order/
The Witcher video games are created by CD Projekt Red: https://thewitcher.com/en/
The Witcher Tabletop RPG is created by R. Talsorian Games: https://rtalsoriangames.com/category/the-witcher/
Music by Eric Matyas: soundimage.org