What actually are Pals?

This is a lore question regarding what Pals actually are. Like what qualifies something as being a Pal? Why do Pals seemingly have magic powers?

Like, there are the ones we find in the isles, and for the most part, they can be organised into one group, but there's some specific Pals that get me caught up.

The Xeno Pals: Obviously, these guys are aliens, it's in their name. But where did they come from? Do we know their home world? Or are they more like Deoxys? They aren't the only things that come from space either, we also get supply drops crashing in at terminal velocity. I feel like the Xeno Pals are responsible for that. We have advanced technology in the game, so the packs might be some remnant of a fleet humans built?

Bellanoir: Bellanoir seems more like a God than a Pal to me. From her Paldex entry, it seems like she peered into our universe and has decided that it's our time, I guess. She seems very esoteric but obviously malevolent. Pals can exist beyond our universe, or at least they do. Given that there's two Bellanoir's, this may be more common than we think.

Necromus and Paladius: Based on the statues that can be found around the isles, these two seem to be revered and very, very old, especially given they were once the same entity, but that predates the statues near all the ancient ruins, obviously. They are supposed to be Ying and Yang, which I get, but given their incredible age, I cannot help but feel they predate much of what we know to be Pals in the current era of the game. (If there's any extra lore for these guys, please tell me, Necromus is my favourite Pal ❤️)

I don't want any of this to come off as criticism, I really love this game and I just want to know more about its world beyond my guesses.