That is quite different from the other avatars.
"When Zoe stepped through, she was forever merged with the ancient being"
So she is completely something else form Leona, Diana, Taric. They all got part of aspects power but not merged with the aspect itself. Right?
That would explain why she is "The Aspect of Twilight" because she (in a way) is the aspect if they merged into one.
So that means the Aspect itself completely left Targon Prime and is part of Zoe forever?
This would pretty much confirm the Myisha theory.
What do you think?