The idea of the reapers having stingers coming out of the mouth where inspired by polish folktales where the vampires had a stinger or "finger" coming out of the mouth that they used to suck blood rather than use teeth like the Balkan genus that is the greatest influence on the modern vampire mythology.
When Damescinos mentions the virus that causes vampirism, he says "parvovirus", even closed captioning says "horrible virus" because of the obscurity of the term. Parvovirus IS a true virus type, and meets all the requirements for creating vampires in a fictional environment, the term was too obscure for most people to recognize, other than experts in virology.
When Blade returns to his headquarters early in the movie, Scud remarks, "The Dark Knight Returns!" This is a reference to another comic book character that hunts by night, Batman, who was the subject of a classic comic book miniseries.
Pop Icon Michael Jackson was originally going to have a cameo in the "House of Pain" sequence as a "Vampire Pimp" that Nyssa encounters as she searches the upstairs hall. Jackson had to drop out due to scheduling conflicts and the part was played by a Czech actor. The sequence was ultimately cut out entirely for pacing reasons.
Wesley Snipes, was not always available for each day of filming for this movie, which came out in 2002. During 2002, Wesley starred in 3 other films aside from Blade 2. Instead of waiting for Wesley to become available, the crew shot another actor (who was not Wesley's stunt double) for scenes where it was not necessary to see Wesley's face. The first scene, being where Blade, Scud and Nyssa are riding in the helicopter to meet Damaskinos. The second, was after Nyssa performed an autopsy on the dead reaper and confronts Blade in his quarters about his attitude toward the Bloodpack.
During the Fight With Nomak in the church part of the House of Pain the stain glass wind is a replica of Dr. Strange's (another Marvel character who battles the occult) Medallion the Magical Eye of Amagotto.
In the scene before while entering the vampire club with the Bloodpack, a large neon sign can be seen on top of a building that says in large red letters "Radoo". In the history of Vlad the Impaler (who the legend of Dracula is largely based) history talks of his brother Radu. This name is also often associated with vampire movies as it is deeply ingrained in the Dracula story.
According to Wesley Snipes on the commentary with Goyer, there were four fight choreographers. Donnie Yen who choreographed the "wire fu-esque" sequence with Blade and Nomak in the cathedral in their first fight. Jeff Ward, Clay Fontenot, and Snipes himself. Goyer remarked that there was a "wonderful rivalry" between Yen and Ward/Snipes/Fontenot.
David S. Goyer's original idea was to use Morbius as a primary villain, but Marvel decided they wanted to retain the rights to make an entirely separate franchise out of Morbius - i.e. a Morbius film, so the story was changed slightly and Jared Nomak was created to be used as the primary villain instead.
The early scene in which Scud is watching The Powerpuff Girls (1998) was originally written with him watching an episode of Speed Racer (1967) ("Mahha GoGoGo"). However, the owners of the domestic rights wouldn't allow it.
Blade himself wears Oakley Four sunglasses, the ninja-style vampires who descend near the start of the film to offer Blade a truce are wearing heavily modified Oakley Overthetops, Reinhardt sunglasses are Oakley Square Wires and a further appearance can be seen fleetingly being worn by the fat, bearded vampire towards the end of the film, he is wearing Oakley Mars. All these appearance of Oakley sunglasses throughout of the film are apparently down to Wesley Snipes being big fan of the brand though his sunglasses in Blade (1998) were a pair of BlackFlyz.
Snipes' quoting of Sun Tzu - "Keep your friends close, and your enemies closer," follows references to the works of Sun Tzu in many other Snipes movies including Passenger 57 (1992), Rising Sun (1993) and The Art of War (2000).