This is available at level 35 and can started by enter the Harborage.
Quick walk through consists of the following:
*** Spoiler - click to reveal ***Enter the Harborage
Talk to Sai Sahan
Travel to the Valley of Blades
Enter the Abbey of Blades (Optional: Talk to Sai Sahan)
Find Kasura
Listen to Kasura
Destroy the Sigils (3)
Defeat the Titan
Talk to Kasura
Enter the Ancestral Crypt
Talk to Sai Sahan
Find the Ring of Stendarr's Mercy
Talk to Kasura
Protect the Ancestral Crypt
Talk to Sai Sahan
Return to the Harborage
Give Ring of Stendarr's Mercy to Varen
Reward