Welcome
Trake,
There's an extremely useful priest spell called negative plane protection which will prevent the deadly level draining attacks of the vampires. Also, at the early stages of the game you can buy an axe from Bernard in the copper cornet after you finish the slave quest which slays undead (called Azuredge). There is also a longsword called Daystar which can cast sunray which slaughters the undead. Also look out for the mace of disruption which has similar slaying capabilities to the axe.
If you need spoilers as to where to find these items let me know so I can spoil you
