: Honestly, I don't understand why even Cortana is so crazy about the Mantle,
: let alone why other AIs should care about it. Creating an AI-run utopia in
: and of itself would be a more understandable goal (despite Cortana never
: showing any inclination for such before - hell, she denied being a
: megalomaniac in Halo 2) but why involve the archaic pseudo-religious
: ideology of the Mantle, especially when it has proven to be a bad idea in
: the past? Aren't AIs supposed to be, y'know, intelligent?

: It really does seem to me that the villain in H5 was originally supposed to
: be a digitized Didact and they changed it to Cortana rather late in
: development, which would explain why H5 Cortana's goals and dialogue line
: up so perfectly with the Didact's.

The Next 72 Hours comic series came out in August 2014, and we knew what was going to happen in those issues for at least weeks if not months beforehand, like all the comics. They're done pretty far in advance (one of the reasons why despite getting immediate criticisms on some aspects of Escalation, it took so long for, say, the art to improve.)

If Cortana's role was supposed to be filled by the Didact, they would have had to change it the better part of a year and a half or longer before release. It doesn't seem that likely to me that her role is a sudden substitution.

As for why Cortana would be "stupid" enough to fall into the same trap as the Forerunners... when you're a super-intelligent being who plans on leading a bunch of super-intelligent beings, you might just think that you're better than those fallible meatbags from 100,000 years ago.

As for why the AIs would care about humanity at all, I think there's a bit of an unstated envy on the AI's position. From what we know, they still retain some memories or impressions from their physical bases, not to mention subconscious and personality elements. Black Box stands out like a sore thumb from some pretty human-like AIs (if you can decide what you want to be, the fact that they almost all choose human avatars says something about how they're still bound by some vestiges of organic life.) Basically, even if from a dispassionate perspective AIs shouldn't feel any ties to humanity... it's clear they still do (hence why Sloan tries to get his people off-planet before he bugs off, why BB despite his "pure thought" shell genuinely cares for those put in his charge, etc.)