: In Eternal's continuity, Durandal-Thoth escaped Outside under their own power
: at some unknown time after the Last Battle of Lh'owon (presumably in their
: Jjaro dreadnaught Manus Celer Dei, which has its own cybernetic junction),
: did whatever they felt like doing with their godlike power for however
: long, and then one day sitting around watching the universe end (again,
: perhaps), a lightbulb came on and they realized how important Marcus is to
: history (the narration of the Infinity end screen), and intervened as seen
: in Eternal to eventually team up with Marcus and try to fight the rest of
: the Jjaro's prescribed doom.
The ending screen seems to be Durandal humbling himself before the player (which just about NEVER happened until the closure), calling you "Destiny." This seems to mean that, no matter what happens, you will jump timelines to change the course of history toward its one true destiny; the destiny that you are in control of, not Durandal/Thoth. This is a sentiment that speaks volumes for the player's agency, because up until the end, it always seemed like the AIs were pulling the strings, telling you what to do and going at each other, and you're forced to be on the side of whichever one has abducted you.
That moment, when Durandal realized that you were the one that guided everything to its final destination, when he worked so hard to be the one calling the shots and escape the closure: [insert something profound here because I gave up thinking of a good line to end this post on]