Zoe vs Myisha

Myisha in the origin story is described in detail as Zoe's exact appearance. But in Zoe's lore, she was just a girl chosen by an Aspect of Twilight that gives her the opportunity to "see the world". Myisha does also seem more serious and intelligent than Zoe. In Zoe's lore, she doesn't quite know what she's doing. She tries to access a portal but when it fails, she understands that she still has to complete something in the world she's in before the portal will open. That's why I say that Zoe doesn't quite know what she's doing. The lore also says her presence causes cataclysms without effort or malice, explaining the "breezy nonchalance" in which she approaches her duties. That legitimately says she doesn't want to cause harm. But Myisha does want to cause harm. He manipulates Ta'anaka into killing most of his brothers/sisters, and finishes Ta'anaka off herself.

So if Myisha and Zoe have the exact same appearance but different personalities, who are they? Are they the same person or are they different, only dawning the childlike appearance Zoe was born with as a mortal?