Deep Winter

Deep Winter was the Artificial Intelligence assigned to the survey team on planet Onyx, Zone 67. He took the form of an old man with a snowy cape that blew snowflakes and ice as it moved.

Though it is never specifically mentioned, Deep Winter seems to have replaced Eternal Spring when the "smart" AI died in 2537. Deep Winter was a 5th generation "smart" AI, which may possess longer lifespans than previous generations of UNSC AI, as it seems he lived from 2537 until 2551, double the number of years a 3rd generation smart AI lives. However, it is also possible that a different AI took Eternal Spring's place (Likely named after the season of Autumn/Fall, if the names of the other three AI that worked for the Onyx survey team are any indication), lived out an operational lifespan of seven years, and was subsequently replaced by Deep Winter.

Deep Winter was very talkative. He seemed to enjoy the company of Kurt-051, SCPO Mendez, and the Spartan-IIIs at Camp Currahee to the south. Deep Winter showed great concern for the young Spartans, and often acted in what he thought to be their best interest, even when not ordered to. He monitored the progress and actions of the Beta Company Spartans even after they graduated, and then monitored the progress of the Gamma Company Spartans as well. He discovered the illegal drugs used in the augmentation process of the Gammas, and tried to warn Kurt-051 via Slipspace COM Launcher. He went offline soon after, but left files for Kurt to trace the source of the drugs. Ironically, Kurt was the one who was responsible for them.

He was replaced by a new "smart" AI, Endless Summer.