f course as expected the game has a lot of questions yo be answered So why is Cortana the enemy in this game and obviously she is trying to bring the galaxy back to a state of peace witch was already established by the forerunners before we as humans starts traveling space and ended up releasing the flood. The war the humans started is the reason that the Didactic ened up in prison and release in halo 4
Cortana has been be coming more human thought the game. Ad she has been developing feeling for him and out of the blue John is ready to kill her. When she saved his life. The are slowly starting to develop the seame relationship that the didactic and the librarian have the things that helps you save John at the end mentioned that it is possible for Cortana to achieve a physical form.