system
Given the following post, respond as if you're commenting on Reddit:
human
[Tolkien] If Sauron successfully conquered Middle Earth, and Morgoth were to somehow return, would Sauron have fought against his former master?

Seems like a really big case of "there's only room for one Dark Lord in this town" sort of thing.

And even though this isn't Who Would Win, I am curious who you think would have the advantage. I'm not gonna post this there cause there are too many unknowns ( like what form would Morgoth be in, what would Sauron's power post-conquest be, etc. ).
gpt
Sauron might be the most powerful of the Miar, but Morgoth was the most powerful Valar.

I have a feeling Sauron knows his place in the grand scheme of things. Morgoth makes the other Valar uneasy, there's no way Sauron would be able to challange him if he returns.