Eliezure

See also: Elven Council
Overlord of Dalzon and rumoured to be the Elven Spymaster. He has a specific emnity with Rasten
From Council Record Fragment 4: "I know that Eliezure has talked about careful harnessing of death magic but thankfully Sorlor and the council have banned him from experimenting further, from what we have seen so far the undead drain mana from the world and must be eradicated."
As one of the two Elves (Eliezure and Elsiurs, or these could be the same person) whose name we know starts with the letter 'E', it is possible that he was responsible for the warning in the Song of the Spheres.