Who was the antagonist of Halo 5?343 industries
I mean It really is though.
The more that comes out, the more abundantly clear it is that the writing staff have had had no idea where they were going with since Escalation.
Just look at how they've changed their escusre for Cortana going full Trump in Halo 5 constantly
-In Halo 5 it was " Dae Cortana iz Halsey and Halsey iz monster™ lol, but she's still not evil" (sponsored by Karen Traviss)
-Mythos comes out and implies the Domain fundamentally changed her into what she is now
-Then we get Domain Splinter telling us Cortana was still rampant
-Then 343i retcons part of Halo 4 in a Loot Crate to imply she was evil since then
-And now in another fucking Loot Crate she has the logic plauge.
AND THAT'S JUST
Compare that to everything surrounding Halo 4 where all things pointed to the same direction for the series: Learning more about the Forerunners, The reclaimation and the flood coming back.