The cover of the letter you got from an undead said, "To Eron." When you asked Liske about it, she told you that Endyon, a Guardian Sentinel, used that name before he ascended. When you delivered the letter to Endyon, he said that his long-lost brother had written it. When you told him that you retrieved the letter from one of the undead, he shed tears. You told Liske what happened, and she told you to tell Miobera. You told Miobera the tale.