This thread will contain spoilers so only read if you have finished up to episode 6 of season 4
I believe that Aurene did not die because of the episode long live the Lich where she absorbed Palawa Joko. Palawa Joko during this episode made use of Mesmer magic which Aurene would have absorbed along with the ability to traverse the mists as he was known to do.
The reason the death was convincing was because she had to make it appear that way. It’s an illusion like the ones we’ve had to use within the story. I wouldn’t be surprised if we really do see a “branded Aurene” next episode as a boss fight and when we kill it it shatters.
War eternal could also be referring to the fissure of woe a place in the mists once ruled by Balthazar. It would make sense that Kralkatorrik to retreat there after the fight it just had to rebuild its power. I think that Kralkatorrik will try bringing part of the area to the real land of Tyria as demonstrated in episode 4.
If this happens then Aurene would likely let it happen as she can also have control over the realm itself due to her proximity from Balthazar in the finale of path of fire.
Palawa Jokos greatest trick was letting the world think that he was dead.
Mesmer can manipulate energy to make it seem like another