Take the scroll that Nathaniel gives you and travel to the Eternal Throne in the Kingdom of the Dead. Go and have a chat with the Chancellor about it. He will give you a new quest – “The Chancellor’s Quarry” and update your quest log for you. Return to Nathaniel and enlighten him to the news.
Nathaniel will then send you to have a chat with Muria in the Forge Lands. Return to the Forgelands and speak to the Shaman at Tri-Forge. After talking to Muria, return to Nathaniel once more to complete the quest.