Serina

"It was a pleasure and an honor to serve with you, sir. Do look after everyone for me, would you? Goodbye, Captain. Serina out."

- Serina's final report to Captain Cutter.

Serina (AI Serial Number: SNA 1292-4) was a third-generation "Smart" AI that was assigned to the, a modified  commissioned by the UNSC Navy. Serina's avatar was a young woman with long hair and she spoke with a distinct British accent.

Creation
Serina was created by Daedalia Technology, a Martian firm, on January 7, 2530. Serina was considered their greatest work of that era, being an omni-capable AI that displayed both impressive intellectual capacity and remarkable computational efficiency.

UNSC Spirit of Fire
Serina replaced the previous shipboard AI of the Spirit of Fire, although she had a somewhat rocky period of acclimation to the ship's unorthodox crew. During her service aboard the Spirit, Serina and Nurse Lulu Hershey started to have "girly" discussions together during the latter's night shifts in the ship's medical bay.

During 2531, Serina was present in the final battles of the Harvest campaign as well as the Battle for Arcadia and the Battle of Trove, providing the crew with intelligence on the various situations they encountered. After the destruction of Trove, Serina, along with the rest of the crew of the Spirit, were left stranded far beyond human-controlled space without a Shaw-Fujikawa Translight Engine.

Working alone
On the next six years, Serina would focus her efforts on designing and modifying vehicles and weapons for the Spirit of Fire crew, including modification for the M808S Scorpion and the HRUNTING Mark III (B) Cyclops, and weaponizing cryotechnology for UNSC use, like the ZAV-48 Frostraven, the Tundra M88 Bison APC with a vacuum energy siphon, and the possibility of Hellbringers making use of cryoweapons.

Rampancy and end of service
In 2537, six years after the events on Trove, Serina had begun to fall into the early stages of rampancy, but continued her essential functions on the Spirit. On January 1, Serina sought to conduct routine maintenance aboard the vessel, awakening several engineers from cryo-sleep. One of them, Violeta Maldini was then attacked by a Pod infector that had been nesting out of sight after the events on the Shield World, infecting her. Serina imposed lockdown on cryo chamber Foxtrot 7, and did not kill the parasite as the onset of her rampancy led her to be more interested in studying it, neglecting the possible danger it presented to the rest of the crew. She watched Maldini mutate into a carrier form, breeding new infection forms and utilizing Maldini's knowledge of cryo chamber codes to awaken more crew members to infect. Realizing her mistake as the Flood threatened to breach quarantine, Serina awoke Professor Ellen Anders (and, indirectly, Jerome-092) who managed to kill all Flood aboard the vessel, ensuring the survival of the Spirit and its remaining crew.

After these events, the now rampant Serina began her final dispensation, set up by Anders, on January 4, leaving one final status report for Captain Cutter upon his eventual awakening and was soon after completely terminated. One of her final acts was quietly restarting production lines aboard the Spirit of Fire to replenish materiel that would later prove pivotal against the Banished.

As part of the crew's hope to leave a trail, Serina created a series of preprogramed maintenance sheds and data drops. As per a promise she and Cutter made to John Forge, Serina included in these a message Forge had recorded for his daughter. The UNSC recovered at least one of these with the data falling into the hands of 343 Guilty Spark during his time with the UNSC. In 2557, Spark was able to explain to Rion her father's sacrifice and give her the message that Serina had kept her promise and left behind for Rion.

Personality
Serina had a very sarcastic and detached nature. She frequently seemed to disregard the lives of others, even her own ship's crew - such as when the Spirit of Fire was slowly being pulled inside Trove - almost always responding to their peril with some curious remark or dark joke. Although prone to sarcastic comments and exhibiting a seemingly uncaring attitude, she was more compassionate than she seemed.

She also appeared to have a fascination with human relationships. Knowing the crew of the Spirit of Fire may be on a one-way trip, Serina manufactured and delivered fake emails from family members to the crew celebrating Valentine's Day. No one ever suspected her of this deception.

Serina also had several fragments of memories from her donor. Several of these memories include food, the smell of flowers, the feeling of grass on her feet, and a lot of other little moments. Relating to this during her "free" time, she tried to remember what chocolate tastes like, with little success. She also ran detailed simulations based on the memory of when her donor kissed a boy.

Trivia

 * Serina was voiced by Courtenay Taylor for Halo Wars and Halo Wars 2, who also voiced an Army trooper in Halo: Reach.
 * Serina's line "Spinning up FTL drive" may be a reference to the re-imagined Battlestar Galactica, in which the phrase is used when the Fleet jumps.
 * Serina's British accent may have been chosen as a reference to Cortana, as the original draft of Halo: Combat Evolved's script had her planned to speak with one, but was later removed in favor of Jen Taylor's natural voice.
 * On July 25, 2017, Serina was added as a multiplayer leader for Halo Wars 2 alongside and in a bundle with Halo Wars 2: Operation: SPEARBREAKER.

List of appearances

 * Halo Wars: Genesis
 * Halo Wars
 * Halo Mythos
 * Halo: Tales from Slipspace
 * Something Has Happened
 * Halo: Smoke and Shadow
 * Halo Wars 2
 * Halo: Renegades