The ghostly robe is part of the Ghostly Robes set obtained from the Curse of the Empty Lord miniquest. It is a piece of clothing that belonged to Valdez, the ghost found near Glarial's Tomb, which players can obtain after starting the miniquest.
There are no requirements to wear and, when worn with the other pieces, the player appears 'ghostlike' (i.e. see-through). Multiple pieces may be obtained through the drop trick.
If lost after obtaining it, it can be purchased from Perdu for 45,000 coins.
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