Who is Kaguya actually?

Hello dear Naruto community, I have a few questions about Kaguya. First of all, where do Kaguya and the god tree come from? Actually, she fell from the sky with the god tree, but where do they both come from and why do they come to earth. Secondly, Kaguya said that others will come to…

Hinata vs Kawaki?

Just as an example. If Hinata comes from that dimension, could she activate the Tenseiregan? Sorry if I spelled it wrong. It's what Toneri had. She's actually descended from an Otsutsuki, right? That's why she's the Byakugan princess. Or if Toneri is still alive, couldn't she kill him, then gain karma, and then use the…