Rust Blaster

At a academy set in a city full of 'demons' or 'vampires' as they call them. Every vampire is born with a weapon that is the base of their 'power' and each weapon is different. Every so often a human is admitted to the academy if they're more powerful or different then normal humans. Every 1000 years a vampire is born with out one and he comes to find out that a human is his weapon. Said human shares his blood with the vampire and then turns into that weapon. This human vessel holds a holy weapon that can defeat any human or vampire it goes against.

Later discoveries indicate that the city is actually a gateway to the vampires true realm and that the vampires living in the human realm are Dhamphires [Half breeds] and have been training to protect the human world from these real vampires who drink human blood and kill as they please.

But... The vampires have not stayed dormant for a 1000 years. They too have created a weapon to combat the humans holy weapon. A war has now begun and the two must combat against one another for the fate of the human world and all that reside in it.