But would either one of them be able to die? Nozdormu exist simultaneously with all of time. Past, present and future. I do not know to what extent Ultimecia's powers go but if she has complete control over time, this could be an eternal battle right?
Time compression Ultimecia rules not just the entire universe, but all of time as well. Nozdormu might be in all time, but Ultimecia rules it, he would be fudged in this fight.
Rule it in what way? Is she timeless like Nozdormu? Because Nozdormu may live in all time, but he live in no time as well. His lair is timeless, which means it is out of her grasp if she controls time. How does she control it? By thought does it have a simultaneously past, present and future flow trough her mind? Or does she simply have the ability to handpick time?
She doesn't control time. The most impressive thing she did, in relation to time and space, was absorb part of it. But she was defeated before absorbing everything.
Only if she had succeeded, Ultimecia would be able to control all of time. The Ultimecia we saw could only absorb it. She is a time devourer.
Can she affect herself in time? I mean, Nozdormu can freeze all things around him. He can create something I believe was called a "time-stasis" which freeze set targets in a timeless barrier manipulated and completely controled by himself. In order to counter this, you too have to be in control of time.
If Ultimecia would become frozen in time, would she be able to counter it, or would her fate be in Nozdormu's paws?
IIRC Ulti froze the party in time, in Timber. It's one of the videos in her Respect Thread(I posted the link to it). And she froze time in the trailer of Dissidia too.
Sargeras/Kil'Jaeden/Archimonde with the well of eternity would basically be omnipotent. Should we use what a character could become rather than what a character actually is?
Nozdormu with the demon soul would be even harder to kill than he already is.
This was just Ultimecia from the game, and not a theory version. I was under the impressing when I made the thread that she had powers over time efficient enough to match Nozdormu.
Aman'Thul would definately be able to do so too. That does not mean he IS time. Just because Ultimecia can compress time, does not mean she is absolute in a battle in time.