I haven't posted here before, but I have a theory about the Didact, one that I use evidence from the books as well as games to back up. Anyway, my theory is that there aremore than two didacts, atleast 3. First, we have the Didact before Born-Stellar, then the Didact that born-stellar becomes. Both of those Didacts were more benevolent towards humans, though though Born-Stellar is the only one that probably actually liked humans, with the other being more ambivalent towards them. Than we have the Didact that the chief fights. I think he was the very first Didact, before the Didact that was in a Cryptum on Earth (who is executed by Faber) and the Born-Stellar Didact. The Born-Stellar Didact is the one who activated the Halo array, and he is the one who has the dialog recorded in the terminals in Halo 3. That gives us 3 Didacts. However, I actually believe there could be even more than that. My evidence for this is mainly a quote from Didacot (not sure if in books or games, found it on the halo nation), but the quote is sourced as "Didact, 5th Permutation". That implies either its a quote from a book called 5th Permutation (unlikely, because not underlined), or that it came from the 5th Didact. That puts us at at least 5 Didacts. We know that a Didact activated the Halo array, but we also know it could not have been the Didact in Halo 4, he was locked up and if you watch the terminal videos, he wanted to fight the Flood using the Promethean Knights rather than even build the Halo array. Anyway, there is also speculation that the evil Didact is still alive. I certainly see the possibility that he survived somehow, based on evidence in game (could also indicate Cortana's survival in some form). That evidence is mainly that some of the Promethean Knights had memories from New Phoenix, meaning that the Composer managed to send the data back to Requiem (or wherever else it sent the data). This means that the Didact could have also been transmitted back. As for Halsey being an enemy, I don't see that as being the true scenario, more likely she is just adapting to her situation until she can find a way to get back in the good graces of the UNSC. Again, I have in game evidence for this. The evidence is the end of Halo: Reach, where Halsey gives a memorial speech to Noble 6. That takes place a couple of decades after Halo 4 takes place. While with Jul, she is simply tricking him into thinking she is on his side. Considering Halsey's actions earlier in her life, this seems more likely. Fun idea though.