Aight, so we can do this either modern, or high fantasy, and some details will change based on that, but here's what I've got.


So this super-old-ass vampire, not like, the original vampire, but like, his youngest vampire-spawn, decides that he's tired of just hanging out and doing vampire things, so he takes some necromancy classes, and figures out how to raise an army of the dead. Then he figures he might as well go conquer the world. For the sake of politeness, he decides to start away from his sibling-rivals, figuring they could sit around and do vampire things until he showed up again, and hopefully he'd be more powerful than them by that time, since he'd be king of the rest of the world. That was the plan at least.

So he gets to a good place to start, he figures, and starts creating himself some vampire thralls to serve as lieutenants and distractions and such, before he starts looting local graveyards and really getting the ball rolling on his world domination plot. About a year later, and progress is slow, since zombies are slow, but he's undefeated so far. Of course, now the church is getting involved, and the pope's all like "We need a crusade up in this bitch" and he calls up anyone not doing much of anything and blesses them all and tells them to go fuck up evil. And then actual paladins and templars show up too, wanting to actually help. So now there's holy warriors and their retinues scouring the countryside murdering motherfuckers and generally getting in the way of the vampire lord's world domination plot. This gets a whole lot worse when said vampire ransacks a cathedral and raises the entire contents of its catacombs to help with his plot. The pope demands that just about everyone take up arms and start killing creatures of the night, and the pope himself even calls up his personal retinue and heads out to help with the war effort. 

At some point, one of the vampire lord's newly raised, extra-fresh lieutenants, knowing that they are about as useful as a zombie at this point, since they haven't eaten anyone, decides that they don't want to play. The only problem, obviously, is that hibernating without eating anyone could have disastrous results. But it can't be worse than getting fucked up by an angry paladin, right? So they sneak off and hide out in an as-yet unransacked church, the small catacombs beneath are nice and dark, and largely untended thanks to all the busybodies out fighting. So the lieutenant hops into one of them little alcoves in the wall and goes to sleep.

Then a whole bunch of time passes. pretty well all the other vampires get killed, or at least decide that trying to conquer the world is a fuck-off terrible idea, and cut that shit out. And anyone who might have known about or noticed the vampire in the catacombs of the church is dead. 

Now, if you want to go modern, maybe someone decides they wanna renovate the church or whatever, and some dumbass hurts himself and gets enough blood on the vampire to initial Operation Wake Up And Eat Some Motherfuckers. And then the vampire, confused manages to wake up after the sun sets, only to find that the world is nothing like it used to be. And on top of that, all their clothes have rotted off, so they're naked and look all gross because they haven't eaten anyone in centuries. So then maybe they sneak into the church proper and eat some hapless late-night churchgoers and put together a largely blood-free outfit and go see what the rest of the world looks like... Not sure what happens at this point...

If you wanna go with fantasy then maybe some dumbass priest, obsessed with keep records, is a little too vigorous in sharpening his quill or something, and cuts himself bad enough to wake up the vampire and get eaten, and then... Again, honestly, I'm not sure what happens after the vampire wakes up... I just got that far and thought we might be able to work with it...