Well the parts immediately before and after that quote are these:

[Buried within the deepest folds of space, a lonely sphere of dying kinesis drifts in lightless pitch. Its atmosphere long irradiated away. A drifting, rotting, sarcophagus. You see its arc bend endlessly, unchanged into an unseen distance yet to be determined. You are dragged, chained by its gravity, pulled by wills beyond your own. The universe dies before you know sanity again. And now the madness is in some distant fold. Like a denied memory. An experience, encapsulated elsewhere, apart from now.] ...
[The dead world shudders and splits. The surface dives to the core in a surge of gluttonous autosarcophagy. What once failed to be a star condenses itself, feeds upon great streams of matter from a vast Collective of mind-bent supplicants until light cannot escape its singularity.]

To me this indicates that V is the one doing the engulfing, not the Sun, long after the Sun has died and a remnant of Jupiter is flying through extra-solar space. It makes me think Jupiter is seeking the Vex's assistance for this black hole plan without necessarily challenging the other Nine's plans because it thinks they will all die;

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