he slashes Lahabrea with Ascalon suggest the complete opposite, that Thordan
consumed Lahabrea's soul as aether to sustain himself, much like Leviathan did to that transcended sahagin elder back in
Through the Maelstrom - he even commented that an Ascian's soul is just aether:

Originally Posted by
Heavensward Main Scenario Quest 'Heavensward'
King Thordan: "Your contempt for man has proven your undoing Ascian. As my first act as god-king, I do hereby sentence you to die."
Lahabrea: "What?!"
(Thordan slashes Lahabrea with one stroke and destroys him)
Lahabrea: "Aaaaaaargggh!!!!"
(Lahabrea dissipates into his dark aether and coalesces around the Eye within the blade's hilt before disappearing, not the usual votex style warp out effect when Ascians teleport away, but instead he just... fades away)
Thordan: "Gods feed upon aether. It matters not what form that aether takes. Ascian souls are no exception. With this power, I shall put an end to a thousand years of conflict."
Thordan: "Be they sown by Ascian, dragon or Primal, wheresoever the seeds of chaos threaten to quicken, I shall excise them with my divine blade and bring order to the world."
Of course after Lahabrea's demise, you see his aether coalasce around the Eye within Ascalon's hilt, so I don't know, he indeed
might have been absorbed into Nidhogg and not consumed as a tasty aetheric snack by Thordan, but I hope that is not the case, as I'm tired of Lahabrea and his inane scheming and really do hope this is
finally the end of the bastard.