Continuity mistake: When Ryan Reynolds falls into the room he was chained up in after he gets scared by the vampire dogs, he hits the bar above and bends it. However, when he runs over to Blade after he has just defeated Dracula, you can get a perfect view of a now perfectly straight bar.
Continuity mistake: When King tells Danica that her hair is ridiculous, she touches the hair above her head. The shot changes and she's now touching the sides of her head.
Revealing mistake: In the scene where Blade kicks Triple H and he goes through the wall, you can see the hole in the wall before he flies through it.
Continuity mistake: Near the middle of the film where we see Drake in the vampire shop. Just after he throws the guy through the window and then proceeds to bite the girl, in one shot we see Drake holding her down with his left hand on her stomach, the camera cuts to a closer view of her neck, he now has his other hand on her forehead. (00:48:30)
Continuity mistake: Close to the end of the movie, Danica Talos and Hannibal King are fighting, Danica throws Hannibal through a painting, in the shot where he lands, look behind him, you see Danica in front of the painting, then when it goes back to Danica, she is emerging from behind the painting. (01:42:15)
Continuity mistake: Just after Abigail and Hannibal have rescued Blade, and are walking back to the new hideout, the camera cuts to a little girl who stands at the middle of the metal railings, but when Blade passes the camera it cuts to a closeup and the girl now stands at the end of that particular railing. (00:39:50)
Continuity mistake: At the train station when the kid vampires are looking for someone to eat, the blonde vampire skates past the elevators and crashes into a garbage can, the following shot he is standing at the window. (00:18:10)
Continuity mistake: Near the end of the film when Hannibal is handcuffed to the floor and we see Danica walk up to him, then ask her brother to bring her the chair. In this shot we see Triple H behind Hannibal, but in the following shot he is still to the left of the screen, then the shot returns to Hannibal and he is now back behind him. (01:19:50)
Continuity mistake: When Blade speaks with Dracula at the top of the building the sun changes in every shot.
Continuity mistake: At the beginning of the movie when the four vampires are in the pyramid, the vampire with the scanner in one shot has his light stick across the scanner, in the following shot it is below and pointing down, then the shot after it is back up across the scanner. (00:03:15)
Continuity mistake: Just after Dr Vance has talked with Blade, he takes a needle out of a pack which is on a table on the left side of the room which you can see in the two way mirror, but in the following shot the two way mirror is behind him. (00:31:20)
Other mistake: At the end we see the reflection of a street in Blade's sunglasses but nothing is reversed like it should be (example: the taillights of the cars can be seen on the right side, they should be on the left in the reflection).
Continuity mistake: Hannibal wears a "Hello my name is" tag that seems to slightly change condition and placement during the rescue of Blade from the familiars. Then when they get back to the Nightstalker lair, there's a close-up in which the tag looks nearly new.
Other mistake: When Blade and Abigail come to rescue Hannibal, Blade throws Triple-H through a metal door. Not only can you see the hole in the door before he hits, it you can also see that the door starts to crumple before his body touches it and after he is thrown against it and it lands on the floor, there is no dent.
Factual error: Although the city where Blade Trinity occurs is never named, the involvement of the F.B.I. would suggest somewhere in the United States. However, as Blade chases Drake out onto the rooftops to save the baby Drake stole, you can see the Sears tower spire in Vancouver Canada and the sun burned image of the Hudsons Bay symbol on the wall behind him. So, they are on the roof of The Bay building in Vancouver. (00:56:05)
Continuity mistake: The Daystar Arrow changes size between shots after Blade stabs Drake with it. When it is first fired by Abbigail, it looks to be about the size of a standard arrow (it looks at least 24" long if not longer), but when Blade later picks it up and stabs him with it, it suddenly shrinks in size quite a bit. In a few shots, including the tip, it looks less than a foot long. Only the tip is buried into Drake's chest as shown in the film, so that can't be an explanation. Also nothing in the movie indicates it might have snapped or broken. (Drake caught it and dropped it right before being stabbed with it, which shouldn't have broken it). It literally just suddenly is about half the size it was.
Continuity mistake: At the railway station, when Abigail Whistler begins to take out the first street punk with the silver knife from her boot, her hat comes off, but in all the following shots it is back on. (00:20:40)
Revealing mistake: At the beginning of the movie when the four guys are in the pyramid, one of them bends over and pulls out one of the stones it can easily be seen that the surrounding stones are not real as they bend upwards when the stone is pulled up.
Revealing mistake: When they find Abigail and Blade, Sommerfield is dead and suspended by nothing but wrist restraints above head level. Her arms are bent as if she were standing up. Her arms would be straight if she were dead, since her wrist restraints would be the only thing supporting her body weight. (01:21:08)
Revealing mistake: While Blade is in jail and is being rescued by the Night Stalkers, he is fighting Jarko. He kicks him through the wall. The wall begins to crumble before Jarko's back touches it. (00:33:15)
Answer: It's possible that he followed one of them back to the base. This is feasible since they wouldn't be able to tell that he was following them because of his shape-shifting abilities.