This is not my work. But this is quite telling.
From what I can guess, the “true ending” of the dreaming city is just Savathûn winning.
Not gonna lie, being jabaited like this is absolutely up the alley of Savathûn.
I’m just waiting for the day we get to kill her
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It's been suspected for quite a while that Savathun is going to be the next big boss in the series, like Oryx. She is the sister of Oryx in the lore, and the lore heavily supports this theory.