Vin Diesel had been a Dungeons and Dragons player for many years (he taught Dame Judi Dench to play on the set of The Chronicles of Riddick (2004)). The main character in this movie was partly based on his old Dungeons and Dragons character (Melkor) who was a Witch Hunter. He used one of the third party Dungeons and Dragons books to create the character class, as he loved being a Ranger type, but also like to use a few spells too.
The Last Witch Hunter 2 was announced prior to this movie's release, however, after poor box-office performance in the U.S. (the movie did turn a profit in the worldwide market), and disastrous reviews, the sequel is now in doubt.
Whenever Kaulder breathes on a window to reveal a symbol, that symbol is an Icelandic magical compass to help the bearer find their way through harsh weather without being injured. The name belonging to such magical symbol is Vegvísir.
Kurt Angle is the third professional wrestler to appear in a movie alongside Vin Diesel. The other two are Dwayne "The Rock" Johnson (The Fast and the Furious franchise) and Dave Batista (Riddick (2013) and the Marvel Cinematic Universe).