(at around 37 mins) The 'attack dogs' outside of the vampire mansion were actually very docile and playful canines, which were the only dogs available at the time. For the scene where they chase Scott Speedman, director Len Wiseman had to film short clips of the dogs running and later put in sounds of vicious barking. If you look closely though you can see their tails happily wagging back and forth.
Not only in this movie did Kate Beckinsale meet her future husband, director Len Wiseman, but at the time she was in a long term relationship with actor Michael Sheen, who played Lucian. Michael and Kate share a daughter together who appears in the film during a flashback of when Selene was younger. Michael and Len have since become very close friends and have collaborated with each other on Underworld: Rise of the Lycans (2009). Michael and Kate still remain very close and both are raising their daughter equally. Kate has stated that Michael is her best friend and that they still remain very close.
A kiss between Michael and Selene (when she unchains him in Lucian's lab) appears in the trailer but was not included in the theatrical release or on the DVD, but it is on the unrated version of Underworld.
(at around 28 mins) Len Wiseman opted to shoot many of the action and effects sequences live, without computer imagery. In one scene, for instance, a werewolf seems to run more than 50 mph behind a speeding car. This was shot using an elaborate rig towed behind a vehicle, with actor Michael Sheen doing the closeups of the running and the jump onto the car, while the long shot of Lucian running was done by stuntman Todd Schneider.
In the newly released 2017 4k remaster of Underworld, the scene where Michael recounts the events of Sonja's demise when he speaks with Lucian in the film is replaced with the actual scene from Underworld: Rise of the Lycans (2009) instead of the original flashbacks used in the 2003 version.
White Wolf, Inc. and author Nancy A. Collins filed suit against Sony Pictures, Screen Gems, and Lakeshore Entertainment on 4 September 2003 for copyright infringement little more than a week before the theatrical release of Underworld, alleging 17 counts of copyright infringement, and claiming over seventy points of unique similarity between White Wolf's role-playing games, "Vampire: The Masquerade", "Werewolf: The Apocalypse", and their creation, "The World of Darkness", in which the games are set. Nancy A. Collins is the author of a short story, "The Love of Monsters", published in 1994 by White Wolf Inc, and set in the World of Darkness, which she claims the entire plot of Underworld is based on. The suit was settled out of court, for an undisclosed amount.
The name of the city where the film took place is never mentioned. However Michael's address that we can see on Selene's computer is an apparently misspelled Hungarian address (it should be "Lakatos József u. 39." while it is spelled as "Laktos Joszef 39 ut." instead). You can also read "Eötvös utca", a street in the historical downtown of Budapest, many times while driving by to the secret interrogation place and there is an ad in the subway station where the shooting takes place in the beginning of the movie referring to Szentendre which is a small town near Budapest (obviously left there as non-Hungarian viewers don't understand the text anyway).
The underground tunnels used for the Lycan/vampire battle at the end of the movie were mostly shots of the same small rubble set, but shot from different angles and lighting in order to make it look like different locations underground. During the DVD commentary, director Len Wiseman laughed at this fact and pointed out the scenes in which this trick photography was used.
(at around 41 mins) The ancient tome which Selene uses to research the history of Kraven features pages from three different sources, all shown before "The Fall of Lucian." The first, featured on the page with the seals of Amelia, Viktor, and Marcus, is an ancient Hungarian text entitled Funeral Sermon and Prayer. The second is an old Catholic Roman Missal, including the Propers of the Second Mass for All Souls' Day. The third is a book entitled Instructissima Bibliotheca Manualis Concionatoria, which is also featured between pages of the story of the fall of Lucian.
The iconic handguns used by Selene are heavily modified Beretta 92FSes, made to look like the Beretta 93R. They have also been modified to fire in full automatic mode (3-Shot Burst, actually; If you slow down the scenes you can see 3 rounds fire per trigger pull) and contain barrel weights attached (possibly standing in for compensators). They use 20 or 30 round box magazines, she also uses a pair of two-tone Walther P99s fitted with Laser Devices BA-5 laser sights at the bottom of the barrels. The guns have been modified to lessen the weight required on the trigger to fire, almost as if they were fully automatic,- You can see Selene pulling the trigger for every shot, but you hear fully automatic fire. (Most notably in the subway shootout, when Selene fires on the fleeing Werewolf in the train.)
(at around 26 mins) When Selene first encounters Lucien, she gets cornered by Lycans and fires her guns through the floor in order to escape. Eleven years prior, this cinematic stunt was performed by the main character in the 1992 film Nemesis (1992).
At the time of the first film, Kate Beckinsale had been mostly doing period pieces and playing lovely girls. She took the role to shake the image a little. The success of this and Van Helsing turned her into an Action Girl in the 2000s. 2016's Love & Friendship is a return to her period roots.
Many Lycans (including Lucien) use nickel-plated Desert Eagle Mark VIIs chambered in .44 Magnum as their handguns. They are loaded with hollow bullets filled with a special irradiated fluid that emits ultraviolet light: "Sunlight used as a weapon." Selene takes a Desert Eagle loaded with the special bullets off a Lycan warrior, Trix (Todd Schneider) in the beginning of the film. Lucian (Michael Sheen) also has one at the end of the film.
The creators of the series approached Marvel Studios about doing a crossover with the Blade franchise, with Wesley Snipes presumably reprising his role. Marvel declined, saying they wanted to leave the door open to do something with Blade on their own terms.
Director Len Wiseman has stated that the scene of Erika hissing at Michael is the most popular scene in the entire film. Though actress Sophia Myles wore the same size teeth caps as all of the other Vampire actors, Erika's fangs appear to be longer than anyone else's. Len Wiseman comments on this puzzling fact in the DVD commentary. Erika's eyes are described as being violet in the novel, although they are blue in the film. Ironically, Sophia Myles went on to portray Beth Turner, a human woman who falls in love with a vampire in the television series Moonlight. GalleryEdit
The film seems to have been conceived (in part) as a modern update on the old Universal Horror films of the 1930s and 1940s. So instead of black velvet evening gowns and spooky organs, it featured a whole cast of characters in Matrix-inspired black latex trench coats, and its soundtrack prominently featured Evanescence's Amy Lee just as she was becoming a goth icon. It still maintains a pretty loyal cult following (there's a reason it spawned four sequels, after all), but most of what made it seem "modern" in 2003 now makes it seem nearly as dated as the old-fashioned horror films that it was updating.
Kahns rifle is a M4A1 Carbine, fitted with a scope, a laser pointer and a Surefire M500AB tactical flashlight in the foregrip. The lower receiver lacks the "fencing" around the magazine release, which means it's actually an M4 barreled upper receiver mounted onto an early Colt SP1 (original M16) 'slab side' lower receiver. Since so many SP1 lower receivers were converted to full auto fire (for movie use) in the last three decades, this is a common practice.
The setting was similar enough to White Wolf's Old World of Darkness tabletop RPG that there was a legal fracas over it around the time of the first film's release. Otherwise, the film is generally thought of as The Matrix with vampires and werewolves.
A 9mm Heckler & Koch USP Match equipped with a Jet Funnel extended magazine well makes its first appearance when it is given to Selene by Kahn to test out. When she fires it, silver liquid comes out of the target, and we learn that the gun is loaded with Silver Nitrate bullets which were copied from the Lycan's ultraviolet ammunition, and are very lethal to the werewolves as it allows silver to flow into their blood stream. Towards the end of the film, Kraven uses the same USP Match loaded with the same ammunition to shoot and later deliver the coup de grace to Lucien. It should be noted that silver nitrate is actually clear in liquid form, but the liquid used resembles mercury.
"Underworld" was lightly parodied as "The Wreathing" in the 2010 BBC radio/audiobook adaptation of the Simon Brett's "Cast, in Order of Disappearance". The original story (written in 1975) was relocated to the set of the vampire film for the audiobook, and starred Bill Nighy ("Viktor" in the Underworld films) as Charles Paris, a minor British actor and amateur sleuth, engaged to play the role of "Szabec", a middle management vampire in an organised vampire society. The mystery is set around the actors while on and off set for the film. Martine McCutcheon plays a character which is loosely modelled on Kate Beckinsale.
Michael Sheen plays a Lycan (aka) a werewolf who dislikes vampires because of the war in which his vampire girlfriend was killed. In a later movie however he plays a vampire who hates werewolves in the Twilight Saga.