Why Do We Trust What Aurelion Sol Says?
The way Aurelion Sol talks he makes himself out to be a god. But who is to say that his view of himself is accurate? Just as Jihn views himself as an artist, how Aurelion Sol views himself may not be based in reality. He is obviously a being of immense power but I think a lot of these threads on the forums are jumping to conclusions way too quickly that he's the most powerful champion in the game.
I know people will be like "he created and destroyed a star in the teaser!" Did he really? Recall that this "star" flew past mountains in the teaser and actually appeared to be relatively small in size. Yes, Aurelion Sol may be able to create "star like objects" or harness the power of stars but I doubt he could literally put a real star in his hand and crush it like an egg.
TLDR: What a champion says or believes and what reality is are two completely things so calm down. I highly doubt Aurelion Sol is as powerful as he says he is.