Though the name “striga” has its place in Eastern European mythology, the show’s idea of the monster seems to be an amalgamation of several different types of folklore fiends. The strzyga, the shtriga and the strigoi are different regional variations of a vampiric demon spirit. The strzyga is the most prominent one in Polish folklore. According to the Polish Folk Tale Dictionary, the stzryga “is a phantom, although there are messages confirming that sometimes the wraith and the striga were distinguished as two separate demonic beings.”
The show’s depiction of a striga is also close to the Polish myth of a poroneic or a Scandanavian myling. Poroneics and mylings are believed to be what happens when a baby dies before it is baptized in the Christian faith. They become demons and haunt the homes and the lives they were meant to have. A poroneic was also central to a main story quest in The Witcher III: The Wild Hunt, the most recent video game based on Sapkowski’s series.