He'll automatically discard some chewed bones from FryeJacob's blog

Head back to the aviansie from the Eagle's Peak Mountain. They'll tell you your soul is in danger after helping Azzanadra. Describe to them the location of Jaldroacht Pyramid, and they'll issue orders to OSRS GP the Desert Eagle underneath them. Next, you will be advised that Azzanadra must be planning to use the Vault of Souls into ressurect Zaros. Its place is unknown, but it would be in a cursed place.

You are advised the place can be underwater. You're thrown backward, and several spirits seem. At this point, you must run. Proceed to the aviansie and they'll be at a loss for words. Go to the Oracle, and she'll shriek when she finds you moved there. She will inform you that only a legend that wielded an elemental power, and was the master of his mind and body, ever escaped from the vault of souls.

He'll automatically discard some chewed bones. Burn them outside on a pyre ship. When nothing happens, speak to buy RuneScape gold Otto Godblessed about it. He will suggest a potion to assist. Make a rest potion out of spirit weed and snape grass. Use it on your pyre ship, light it, and a spirit will appear and give you a secret. He will state that you need to also wield elemental power and command both body and mind. Go to the elemental workshop to the room that has the zapper seat and across from it's a locked door with all the entire body rune symbol on it* Open it with your key and search some shelves for the book of the elemental spear.