Why did Dakota become the biggest enemy of the galaxy in Halo 5? What's going on here?

Because 343 caters to the mainstream American culture and turns Kotana into a crazy AI, Kotana hopes to complete the control of the whole galaxy through the technology of the pioneers and carry out the unfinished mission of the missionary (the fourth generation BOSS).

Kotana is the heroine in the science fiction game Halo series of Microsoft. She is an intelligent artificial intelligence, manufactured by Dr. Catherine Halsey, and served in the United Nations Space Command, numbered CTN 0452-9.

Role experience

Kotana cortana, like most UNSC artificial intelligence, can be uploaded to some well-equipped combat suits or appear in front of comrades in the form of holography.

After following the sergeant to destroy the first halo, his contact with the sergeant became closer, but this relationship was forced to separate after the second halo incident. She was last seen in the "City of Love", the capital of the Star Alliance infected by the Zerg, and was imprisoned by the leader of the Zerg.

Kotana is the only one who holds the secret of the halo. If she can't be rescued safely, the galaxy will perish with her.