User blog comment:ImperiexSeed/Supernatural Mysteries/@comment-166.137.156.162-20130309015629/@comment-3481504-20130309022536

No, a ghost, being an already dead being, wouldn't die by anything.

Well, lets look at this from a similar scenario.

What would happen in a Cherub was stabbed by an Angel-Killing blade? When these type of beings materialize, they literally become physical, in the sense that they can be touched. From that basis, I think when materialized, they would effectively die by the said weapon.