On the wall in the castle there are several paintings of elder vampires including a rendering of Vlad the Impaler, also known as Dracula.

It was originally thought that this was Kate Beckinsale's last movie playing the character Selene, but Len Wiseman has confirmed a sixth movie is in development with Beckinsale reprising her character.

This is the directorial debut for Anna Foerster who often worked with Roland Emmerich (starting as director of photography for the visual effects camera unit on Independence Day (1996)). Producer Len Wiseman also worked with Emmerich as a prop assistant on Independence Day as well as Stargate (1994) and Godzilla (1998).

The first Underworld film to be rated a 15 certificate in the United Kingdom since Underworld (2003). The other Underworld sequels have been rated an 18.

First movie in the franchise released more than 3 years apart from the previous one.

This is the first time a "Resident Evil" movie and an "Underworld" movie have both been released in the same month. Both franchises are distributed by the parent company Sony.

This movie contains 4 cast members from the Game of Thrones (2011) universe. This includes Charles Dance (Thomas) who portrayed Tywin Lannister, Tobias Menzies (Marius) who portrayed Edmure Tully, James Faulkner (Cassius) who portrays Randyll Tarly and Lara Pulver (Semira) who voiced Lady Elissa Forrestor in Game of Thrones: A Telltale Games Series (2014).

Bradley James has worked with Daisy Head's (Alexia) real life father, Anthony Head in the TV show 'Merlin (2008)'. They played father and son.

Director Anna Foerster and Tobias Menzies (Marius) worked together on the television show Outlander (2014).

The film has been pushed back to early 2017 due to delays.

The ending of Underworld: Blood Wars (2016) is left open, which will lead to the beginning of the sixth film in the series, says producer Len Wiseman. The next movie is also said to be starring Kate Beckinsale one last time. The release date, director, plot and title of the sixth film are yet to be confirmed.

It will be revealed where Michael Corvin has been since disappearing in the preceding film, Underworld Awakening (2012).

It was discovered that Marius was injecting himself with the blood of Michael Corvin near the end of the movie.