December

"Hello, Morgan. It's time we spoke. My code name - is December. My purpose is to help you escape Talos I."

- December upon first contacting Morgan.

December is a reprogrammed Operator that guides Morgan Yu through the Talos I and appears in Prey (2017).

Overview
The chronological successor to October and earlier counterpart of January, December aims to help Morgan escape Talos I.

Background
After Morgan's participation in the Typhon-based Neuromod experiments caused their personality to drift, they hatched a plan to return to Earth and warn humanity about the Typhon as well as Transtar's dangerous research. Morgan, knowing they would soon have their memory reset, created December to guide their future self in stealing Alex Yu's private escape pod.

Morgan was returned to the simulation lab, but continued personality drift as well as the experiment cycle being extended indefinitely without their consent drove them to a psychotic break. Morgan managed a brief escape, during which time they decided to destroy Talos I using the station's self-destruct override. They stored the details of this plan on a new reprogrammed Operator, January. It is unknown if December failed to contact that incarnation of Morgan, or if it did and Morgan simply rejected their previous idea to flee. In either case, Morgan was eventually recaptured and forced back into the simulation.

Prey (2017)
December first makes contact when Morgan enters Psychotronics and tries to convince them to leave Talos I via Alex's executive escape pod. It explains Morgan had previously acquired the access keycard and hidden it in the Neuromod Division, and encourages them to retrieve it.

On top of a cabinet Morgan finds the bug-out bag they'd left for themselves, but Alex had already discovered their sibling's plan and removed the keycard. December asks Morgan to meet it in the Neuromod foyer, stating the office "isn't safe".

If January is still functional at that point it will beat Morgan there and destroy December, calling it a defective remnant of Morgan's earlier plans. Otherwise, December will work with Morgan to access the escape pod in the Arboretum. Unlike January, December actively self-destructs itself once Morgan reaches the escape pod. Even if December is destroyed, the objective to unlock Alex's escape pod remains available to Morgan. Once opened, it can be used to leave Talos I at any time.

Trivia

 * If January is destroyed early enough in the game, December assumes its role in guiding Morgan through the story though in a far more limited capacity. It will not, for example, offer the optional objective Mixed Signals.
 * December speaks in a fragmented, robotic tone, as opposed to January's human-like speech patterns. December also shares a few lines of dialogue with January, evidence that it was based on Morgan as well, though an earlier "version" of them.
 * E-mails between them reveal Danielle Sho and Alex Yu learned Morgan had reprogrammed an Operator, a serious breach of station protocol. It is implied Chief Sho had detected the existence of January, but no mention is made of her being aware of December (or even October).