It had to have been a millennia before Sara had left Earth-199999.
She had stayed until everyone she knew had long passed, the last to move on to the afterlife, was Loki. Even though she is well aware of the concept of death. Not even she, The creator of the multiverse, couldn't pass on with them.
She could visit them anytime she want's. But she doesn't like to do that because it makes her hurt more than it needs to be, as well as not being able to stay there for long periods of time. For if she passes on them all life in the multiverse will cease to exist.
She herself knows that there are infinite realities and worlds. So she knows that she will always find purpose. She had left Earth-199999 and had gone to a world titled Earth-444191846.
A world of spirits, bending, and strange but amazing creatures. Her goal is to guide and help this world, in any way she can.
And find her husband and nephew along the way.
(Book 2 of the Multiverse seiris)
Years before the Siege of Ba Sing Se, General Iroh discovers a young girl among the remains of a decimated Water Tribe village. Raised in the heart of the Fire Nation, she grows close to the young crown prince and accompanies him and Iroh on their adventures.
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**This is an old story I had written in my head years ago when the series was still on Nickelodeon, and most of what I had originally written out was dialogue, so I apologize for any lack of detail or imagery-I don't have much time to devote to it as I'd like. I've read quite a few fanfic stories out there and this one isn't very good in comparison, but I'll post it for others who might find it entertaining--it was certainly entertaining to write.
Also, I understand a lot of readers don't like stories that follow canon. This one does follow the show for the most part, but eventually digresses, follows, and digresses again.
Disclaimer: I own nothing of the world of ATLA, although a few characters were seriously harmed (or killed) in the imagining of this fictional story.