In Blade 1 the reason Deacon is killed is because the ritual was incomplete.A big point is made about how the spirits of heads of the vampire houses are needed for La Magra to be summoned. But before they can do that the blonde vampire kills one of the elders, thus depriving Deacon of the full sacrifice for ascension.
- Seems more likely that they had another elder of this clan to use, but the missing spirit was Blade's.
In Blade 2, the Blood Pack was intended as cannon fodder from the getgoThey acted like badass vampire warriors, but by and large, seemed to be just elite mooks. What chance would they really have had against Blade? The answer is "none, but they weren't supposed to." Rather, they were supposed to distract and weaken Blade, allowing the vastly more skilled Nyssa and Assad to kill him after the Blood Pack was already dead.
- Makes sense. Make them feel like the best of the best, so that when they fight Blade, they distract him by being a bunch of arrogant, posturing idiots while the professionals pick the right time to strike.
The Daystar virus was either far less effective or less widespread then the Nightstalkers hopedThe first clue to this is that Blade was unaffected, despite the Nightstalkers' fears. Backed up by the monologue at the end of the movie that implies that Blade is still hunting, and the fact that vampires are seen in Blade: The Series.
Blade will become the new father of all vampires, just as Drake predictedHe's far too much of a heroic sociopath to live a normal life, so he starts turning 'bad' people into vampires just for the pleasure of hunting them. Inevitably, a few of these get away, and begin transforming others, effectively 'restarting' the vampire race.
The Strain takes place in the Blade universeThe Master is a Reaper, or perhaps a Reaper prototype that Eli was working on, that escaped the purge, and with the annihilation of the vampire race in Blade Trinity, the Master's bloodline is free to conquer Manhattan. Why they're vulnerable to silver is a question, but it may be an unknown side effect of the Daystar virus, or perhaps be because the Master is simply a flawed prototype. Other vampire ancients include Eli and Drake.
The La Magra ritual didn't fail as much as we thought
- Frost took the description of La Magra too literally, the "force of nature" and "turning people just by his presence" are attributed to Drake/Dracula, who by vampire standards was godlike. The only reason the ritual "failed" is because of the exact reason Frost wanted to become La Magra in the first place, because he was turned, not pureblood, if you note the statues around the temple, they kind of look like a more feminine version of Drakes' monster form, which gives rise to the theory that Drake was actually a member of an older protovampire race, and the La Magra ritual is actually a "Kingmaker" or "Champion" ritual, which required all present to be purebloods, which happened to Drake thousands of years ago, but because he was a pure vampire the ritual worked perfectly, whereas Frost being a turned Vampire and using "watered down" purebloods, it only really gave him boosts preestablished abilities, hence why he fell so easily despite apparently being a "god".