The demon oak requires a axe and 2k, and YES it works. I wouldnt advise soloing it. you must got to POH temple and ask Oldrak for a Hallowed Axe (Must have axe + 2k gold on you) and you can enter the demon oak ONE TIME, the only way OUT is Death or Completign it. After that, follow your way south to the vampire house and right click the grave right south of it.