Collect Razorfiend Heart, Crystaline Spider Heart, and Planarian Larvae Heart.
Hail Johon Popoah twice
Go find Paralin Notion and follow dialog.
Go find Master Sergeant Aaramis Daryln and follow dialog.
Go back to Paralin Notion, give 3 hearts to him.
Collect crystalline orb piece from Luminii Crawler, one of the frogs near the bridgehouse, and one from the skellies.
Return to Master Sergeant Aaramis Daryln, follow dialog
Find Captain Ryglot Cupperhide, follow dialog.
Give 3 orb pieces to Captain Ryglot Cupperhide, receive Orb (key to enter Aerin?dar?s lair)