[Private][This is all information from the latest chapter...lol]
All of our weapons are infused with special spells that react to vampires. They cannot be be used by humans or vampires, usually. The Kuran family has been known to have the ability to wield them, which stands to reason that the have something to do with how we obtained our powers in the first place. The weapon can be anything, swords, staffs, guns...but they inhibit the regenerative process and prevent them from healing themselves. Depending on their level, the easier it is to kill them.
...the purebloods found a way to use a Hunter in their battles and made sure he had the ability to kill them. The developed a pureblood killing vampire hunter over several years.