This is the reward for the quest Elisi's Fate. On the last leg of the quest, you need to turn in three Erudin Defenders Blades, and Elisi's Medallion. Apparently, Elisi's Medallion doesn't exist, but I did turn in the Talisman of Gaerin and got the reward.
The Erudin Defenders Blade drops in Crypt of Nadox off of zombies, while the Talisman of Gaerin drops off of Captain Bloodblade in Dulak's Harbor.