My speculation: Anastasia lost her son to the machinations of the Heavenly Principles, and so she's planning to declare war on Celestia to get revenge. She also seems to have a very personal beef with Ronova, who may have killed her son on HP's orders.

Knowing this game, wonder if they'll be mother and son
or
A mother and son "with a twist".

At least it isn't another Elysia.

Runty said in comment #2610331:

My speculation: Anastasia lost her son to the machinations of the Heavenly Principles, and so she's planning to declare war on Celestia to get revenge. She also seems to have a very personal beef with Ronova, who may have killed her son on HP's orders.

HP Literally cut her lover and turned into gnosis

Aremandru said in comment #2610501:

HP Literally cut her lover and turned into gnosis

It's unlikely that Saarelainen was Anastasya's lover. People I asked on Discord say that theory has a lot of holes in it.

But I suppose we'll find out the truth soon enough.

EDIT: Turns out I'm wrong. But we still don't know the exact details.