Originally Posted by
DeicideUH
The Nathanos short story sets up a precedent and explains why more undead like him can't be made right now, but it also opens the possibility that things can change in the future. How? Well, it explains that, without the necromantic power of the Lich King, the Val'kyr need to sacrifice part of themselves to make these advanced undead.
So, there's two ways Sylvanas could change that limitation:
- Getting more Val'kyr
or
- Finding a power source that her existing Val'kyr could use to empower the ritual
The first possibility is very unlikely, but what about the second one? Powerful artifacts are scattered everywhere in Azeroth. What if Sylvanas can find one of them? I mean, Blizzard could very well say Helya's Lantern, now broken, is still a fount of power. (Remember when the chain of the Demon Soul had enough residual power to allow Zaela to dominate drakes in Cataclysm?)
Or Blizzard could even go another way. In Stormheim, we find vampire pirates that were turned into Nathanos-like undead when raiding artifacts from a Vrykul tomb. That quest seem very out of place there, as it has no relation to anything else happening in the zone. What if it's a setup for future Forsaken developments?
And there's even the possibility of Sylvanas making a deal with the Lich King, but I won't go down into that path as there's already a thread about it in the lore forums.
Blizzard has multiple ways to develop the lore. Making Nathanos an advanced form of undead opens the possibility of that being expanded further in the future. Do not count that possibility out.