Gabriela

"Greetings. I am Gabriela, the A.I. caretaker of Outpost Discovery. I will be your guide as you explore the outpost's exhibits and experiences."

- Gabriela welcomes visitors to one of the UNSC's Outpost Discovery locations. Gabriela Castaneda was a United Nations Space Command artificial intelligence entrusted to be the caretaker of an Outpost Discovery on Earth. By late 2553, she was considered to the only one of her kind to contain a complete record of all cataloged human history, having been created near the end of the Human-Covenant War to potentially safeguard humankind's legacy. Once thought lost in the aftermath of the Fall of Reach, she was recovered from Sephune III in the latter half of that year by Linda-058. Gabriela later assisted with the aforementioned Outpost Discovery at major population centers on Earth. When a reclaimed section of an was brought to Earth for inclusion at one of the outposts, Gabriela was instrumental in preventing a catastrophic explosion that a lingering Covenant autonomous security protocol subroutine attempted to trigger.

Loss and recovery
"Athos"

- Linda-058 Gabriela Castaneda was a nascent A.I. matrix when the  was chosen as a vessel of safekeeping for her. She was an invaluable asset that represented humanity's attempt to rebuild—even if from the ground up. She was to serve as a time capsule of sorts—prepared to imbue with rekindled hope after an impossible victory over the Covenant, or to carry on lost history, ensuring humanity's legacy could still be learned. During the Fall of Reach in August 2552, Gabriela was thought lost along with the rest of the ship, which disappeared after the battle. At some point in the latter half of 2553 the Office of Naval Intelligence received a distress signal from the frigate's survivors, coming from the largely Covenant-controlled Sephune III. The Dawn had crashed there following its flight from Reach. Given the possibility that Gabriela remained intact, ONI believed sending one of the few remaining Spartan-IIs, Linda-058, to the planet was worth the risk. As such, she was briefed within twenty-four hours of the signal's discovery. She was not informed concerning Gabriela, however, instead being told her mission was to assassinate Doctor Chen Bax, a scientist who had tried to steal classified technology but who had also been thought killed at Reach. Linda was told ONI couldn't afford to have either Chen or whatever he left Reach with fall into enemy hands.

After meeting up with the ship's survivors Linda elected to hold off on killing Doctor Chen and before long Athos, the artificial intelligence accompanying her, was inserted in a terminal in the humans' camp. He soon detected Gabriela and made it known to the Spartan that their mission's parameters had changed. Securing Gabriela, he said, was now the entirely of the operation. Seeing as forces loyal to a resurgent Covenant would be moving on their position in a matter of hours, he also emphasized that if they hadn't found her by that point they would clean the site to make sure the aliens didn't either. When Athos heard Chen mention details about the eighteenth century storming of the Bastille in conversation he thought it possible the doctor had already accessed Gabriela. But once Athos' data crystal chip was being inserted into the Promise of Dawn Chen suddenly asked Linda to give him the code needed to unlock the A.I., saying he knew why the UNSC had sent her to him. He was convinced that he could not let the UNSC have her any more than he could the Covenant. At Linda's refusal, Chen elected to access Gabriela himself. And as it turned out, Athos had just unwittingly unlocked her so that Chen was able to deftly remove his data crystal chip while simultaneously transferring her to an armored matrix. Even so, Linda had little trouble overpowering the man and taking the matrix into her possession.

Outpost Discovery
"Gabriela Castaneda"

- ONI officer After Gabriela was recovered from Sephune III she was entrusted to Spartan-IIIs Hazel-A302 and Owen-B096, who escorted her to Earth. There, she became the caretaker of an Outpost Discovery, a mobile exploratory initiative focused on the education, recruitment, inspiration, and training of the next generation of UNSC personnel. This involved her assistance at various major population centers on Earth, where she acted as a guide during the exploration of each outpost's exhibits and experiences. At each location Gabriela greeted visitors at the "Hall of History", recounting the details of historical events as recent as the Fall of Reach. She had been told that ONI recognized her knowledge to be too important for her to keep it to herself.

When a recovered section of the Supplication of Purity was brought to a United Republic of North America city for use in the training of recruits at an outpost, Gabriela personally lent instruction to the first group to explore it. The exercise was meant to familiarize them with intelligence gathering and the various high-risk boarding maneuvers and strategies commonly undertaken by the UNSC. Once they had entered the reclaimed section along with Ensign Brown, Gabriela asked them to imagine that the ship's commander had initiated a lockdown protocol to trap them following its boarding and was sending a hunter-killer squad to eliminate them. She then directed them to locate maintenance access areas along the bulkhead walls so that they could reconfigure a series of cables to trigger an organized shortage which would interrupt the lockdown in their area. Next, she drew the recruits' attention to a nearby door, where Sangheili glyphs were soon to light up in a particular sequence that, if replicated, would signal the hatchway to open. Just as she was congratulating them, however, she noticed a hostile intelligence which still lingered in the captured ship and appeared to have been awoken by the recruits' actions. Gabriela immediately began cycling the access hatch to open the door they'd been trying to get through before then determining it was likely to explode and so ordering the humans to move away from it. She opened another door on the opposite side of the chamber for them and soon an additional one beyond that, allowing the recruits and ensign to put as much distance as possible between they and the imminent explosion. The Covenant subroutine was blocking Gabriela from Supplication of Purity's internal sensor grid, leaving her ability to help any further vulnerable. Worried that she could be cut out at any moment, she told Brown and the others to disconnect the enemy intelligence by gathering nearby energy core cylinders just before her fear was confirmed and the communication between she and they was severed. When she finally did reestablish a connection she announced she'd discovered the nature of the threat naval intelligence had seemingly missed—an autonomous security protocol subroutine. Gabriela had never encountered anything like it before so she was gathering as much information about it as she could, but she admitted it was putting up quite a fight against her. She eventually managed to neutralize it and make a record of it for future research, but before that the subroutine initiated a self-destruct order set to overload the power conduits at the base of the entire ship section. With the reclaimed corvette now a threat to the entire outpost, she urged those within to quickly locate two key cards used to access the subsystems in their compartment. To her relief, the cards allowed the self-destruct sequence to be halted. Gabriela apologized for the harrowing near-disaster, but thanked the recruits for averting it and told them she considered them to have passed the original exercise with flying colors.

Characteristics
"Linda-058"

- Athos As of late 2553, Gabriela was considered the only artificial intelligence to contain a complete record of all cataloged human history. In addition, she held the secrets of Earth and everywhere else humanity had called home and the sole complete record of all that had been fought for and lost on Reach. She projects an avatar which gives her the appearance of a young woman in uniform with hair prominently combed over to the right side of her head.

Behind the scenes
"Whenever we were designing Gabriela we were looking at the type of uniform that would be suitable for her, for reasons that will become apparent hopefully soon. And, doing the uniform design—because Uncle Sam loves their regulations—and especially the Marine Corps—we are very, very specific about our uniforms and our guidelines."

- Sarah Campbell shares some insight regarding the thought processes behind Gabriela's design and teases information about the character yet to be revealed at the time. During the concepting phase for Gabriela's design, 343 Industries consumer products team artist Sarah Campbell leaned on her experience in the United States Marine Corps to give input on what her uniform should look like. Gabriela was first introduced during the announcement of Halo: Outpost Discovery. Shortly following this announcement, she made her debut appearance within the four-issue comic Halo: Lone Wolf. Her projected avatar will greet guests of Outpost Discovery before they enter the Hall of History at the various event locations, in addition to appearing throughout each section of their show floors. She also is featured as a guide who helps guests be navigated to destinations, unlock secrets, and earn rewards—all through the experience's dedicated mobile application.

Gallery
 File:HLW G1.PNG|Gabriela introduces herself following her recovery from Sephune III. File:HLW G2.PNG|Gabriela collects herself before beginning her recounting of the Fall of Reach. File:HLW_G3.png|Gabriela begins her account of Reach's fall with the mysterious loss of contact with the Visegrád Relay. File:HaloOutpostDiscovery Poster.png|Gabriela is featured prominently on this promotional image for Halo: Outpost Discovery. File:Gabriella.jpg File:HODApp Gabby.PNG|Gabriela greets new users of Outpost Discovery's mobile application. File:HOD Map Orlando.jpg|This map depicting the locations of various Halo: Outpost Discovery attractions in Orlando, Florida shows Gabriela in the bottom-right corner, near the Hall of History. File:HOD Gabrielaplate.jpg|This nameplate was shared by 343 Industries product development manager Scott Jobe. File:HLW ODE.jpg|Gabriela is featured on the cover of a hardcover collection of Halo: Lone Wolf issues exclusive to Halo: Outpost Discovery. File:HOD Gear.png|Gabriela appears on this T-shirt, exclusive to the Outpost Discovery experience. File:OD Shirt.jpg|This T-shirt features Outpost Discovery's key art. File:OD-Shirt2-.jpg|Another T-shirt featuring Gabriela is worn by Florida reporter Greg Fox. 

List of appearances

 * Halo: Lone Wolf
 * Halo: Outpost Discovery