I see you are able to harness the energies of Aluneth. It has been a long time since there was a mage that could control it.
Now, are you prepared to unleash it?
Upon accepting the quest (which happens automatically after completing [98 - 110] Eyes of the Dragon), an "Unstable Arcane Energy" bar appears in your UI. The tooltip description reads: "Gathered arcane energy unleashed by Aluneth from within the Nexus Vault."
As you absorb energy, you gain the "Unstable Arcane Energy" buff, whose description reads: "Absorb energy from Arcane Aberants[sic] and Breaches of Arcane Energy". As the energy bar fills up, your character begins to grow more and more brightly with arcane energy.