Serin Osman

"The only rule is there are no rules."

- A maxim frequently used by Osman

Admiral Serin "Oz" Osman, born Serin Çelik and formerly known as SPARTAN-019, (service number 39489-72738-SO ) is the Commander-in-Chief of the Office of Naval Intelligence, inheriting the role from Admiral Margaret Parangosky after the end of the Human-Covenant War.

Early life
Born in 2511 on the colony of Cascade, Serin Çelik was born to Pinar Çelik, a prostitute and drug addict who completely neglected her daughter. On more than one occasion young Serin resorted to digging through garbage cans for food. Numerous calls to child services were to no avail. The only person who cared for Serin was her teacher, Alkmini Leandro, who regularly brought food to school for her.

SPARTAN-II program and ONI career
"BB sometimes wondered what kind of operational Spartan she would have made, just the averagely terrifying kind or a full-blown angel of death."

- Black-Box

In 2517 Serin was abducted as a Spartan-II candidate. She was given the designation Serin-019 and was trained under Chief Mendez along with the rest of the candidates. Because of her living conditions she (along with Soren-066) was not replaced with a flash clone. She often ate the other candidates' leftover food, a practice for which John-117 teased her.

Serin did not successfully complete the augmentation process, receiving only the genetic and biochemical enhancements before her body started to reject the rest. While she failed the augmentation process, she still possesses a few of the enhancements, although no skeletal augmentation. The Office of Naval Intelligence took custody of her when she was 14 years old; they repaired the damage done by the failed augmentation process, educated her further, and put her into the ONI commanders' program. The other Spartans thought her dead; unlike some of the other washouts later assigned to ONI, she was withdrawn from the program before the funeral ceremony for the Spartans killed in the augmentations. As a result, she remained unaware if the successful Spartans were even told of the fate of the failures.

Considered as a protégé to Admiral Margaret Parangosky, CINCONI, the Admiral groomed the former Spartan for a potential future as her successor. Serin considered herself the only person the Admiral would always forgive even if she failed. In order to hide her status as a former Spartan she adopted the surname "Osman". Though people often assumed she was of Turkish descent based on her name and appearance, she did not actually know whether this was the case; though the information on her pre-Spartan identity was readily available to her, she did not look at her personal file for decades until spontaneously deciding to do so in April 2553.

Kilo-Five
By 2553, Osman held the rank of captain. She was handpicked by Parangosky to lead up a black operations team known as Kilo-Five with the mission to ensure a Sangheili insurgency, keeping the Elites from threatening humanity. The team was composed of the civilian professor and Sangheili expert Evan Phillips; ODSTs Staff Sergeant "Mal" Geffen, Sergeant Lian Devereaux, and Corporal "Vaz" Beloi; and Spartan-II Naomi-010. Using Phillips, Osman arranged a meeting in January with Avu Med 'Telcam, a member of the Servants of the Abiding Truth, on New Llanelli. She agreed to give him weapons to aid in his upcoming insurrection, though this was part of ONI's ploy to destabilize the Sangheili. Later she met with Parangosky to confirm Kilo-Five's members, as well as being given the AI Black-Box and a secondary mission to find Dr. Catherine Halsey, who had disappeared with Spartan Blue Team after the Battle of Onyx. Upon arriving aboard the prowler Osman transitioned the ship into slipspace and revealed her identity to Naomi. Naomi revealed to Osman that the surviving Spartans thought Serin had died. Osman then told the others about her past in the SPARTAN-II program, revealing that it started when she was six years old. This shocked the other members on the ship and angered Naomi-010, creating the very tension Osman had hoped to alleviate.

Reaching New Llanelli, Osman was surprised to see 'Telcam had kept his word; she gave him tagged Sangheili weapons. However, she was approached by Tom Muir, a colonist who had managed to survive on New Llanelli in the wake of the colony's glassing. Brought aboard the ship, Muir angrily questioned Osman about why she was meeting with the Sangheili. Osman made up a story that they were exchanging fallen bodies; Muir fell for this deceit, sparing Osman the trouble of killing him. After a quick mission to DCS agent Mike Spenser from Reynes, Osman went to aid, a ship that had been damaged in orbit of Venezia. However, Venezia's refusal to help Ariadne led to the ship's destruction before Port Stanley could reach it.

Osman went on several missions to aid the Servants of the Abiding Truth, helping them continue their insurrection against Arbiter Thel 'Vadam. She was also present during the UNSC's first diplomatic mission to Sanghelios, accompanying Fleet Admiral Hood as he and the Arbiter formalized the peace between humanity and 'Vadam's allies.

After the shield world formerly housed within the artificial planet Onyx was brought back into normal space, Osman was part of the party that entered the Dyson sphere aboard Kilo-Five's Pelican, Tart-Cart. They met with Dr. Catherine Halsey, CPO Franklin Mendez, and the Spartan-IIs and Spartan-IIIs of Blue Team. Osman personally took Dr. Halsey into custody for "committing acts likely to aid the enemy": during the Battle of Earth, Halsey had diverted a UNSC Navy battle group to Onyx under false pretenses, weakening the homeworld's defenses. Port Stanley subsequently took the survivors to Earth for a debriefing at HIGHCOM Facility Bravo-6.

In March 2553, after participating in the Voi Memorial ceremony, Kilo-Five was tasked with investigating Venezia and its reemerging rebel movement. With Port Stanley holding station near Venezia, Mal and Vaz were inserted to New Tyne while Evan Phillips, accompanied by a fragment of BB, left Kilo-Five to study Sangheili culture on Sanghelios.

Mission on Sanghelios
After an explosion in Ontom, Sanghelios severed Kilo-Five's communication with BB's fragment and Phillips, Osman immediately ordered Kilo-Five to regroup aboard Port Stanley, which then made a slipspace jump to Sanghelios to recover him. Osman had Devereaux fly Tart-Cart to Ontom amid 'Telcam's assault on Vadam while herself coordinating the operation from Port Stanley. While initially failing to locate Phillips in the temple, Kilo-Five eventually recovered him from the Nes'alun keep in Acroli.

Meanwhile, the Fleet's new flagship,, turned the tide over Sanghelios as it decimated the Abiding Truth's forces. As the battle began to turn against the Abiding Truth, Admiral Parangosky ordered Kilo-Five to extract 'Telcam as he was necessary to maintain the imposed stalemate between the two Sangheili factions. With Osman aboard Port Stanley, Kilo-Five headed planetside aboard Tart-Cart and forced 'Telcam into the dropship. While Lord Hood and Infinity openly aided 'Vadam and defeated the attackers, with BB's help, Port Stanley posed as a Kig-Yar pirate ship. Disguised a Shipmistress named "Lahz", Osman and BB covertly destroyed some of 'Vadam's ships under Admiral Parangosky's orders, leaving the Arbiter with a Pyrrhic victory. After the battle, Osman rendezvoused with Tart-Cart and dropped 'Telcam off at New Llanelli for his safety.

During the battle, Osman learned that the Kig-Yar Skirmisher Sav Fel had stolen the Covenant battlecruiser Pious Inquisitor. Tracking down the ship became Kilo-Five's new priority in addition to their investigation on Venezia.

Venezian movement
After the operation on Sanghelios, Vaz and Naomi were inserted on Venezia disguised as UNSC deserters. Shortly after their arrival in New Tyne, they spotted Naomi's father and known Venezian terrorist Staffan Sentzke in the company of Sav Fel, the current possessor of Pious Inquisitor. Shortly thereafter, Osman pulled Naomi off the Venezian infiltration mission and substituted her with Mal as her family ties might compromise the mission.

In April 5, Osman was promoted to rear admiral and a small party was held aboard the Port Stanley in her honor by Kilo-Five.

One week later, when Vaz and Mal were not responding to Osman through their comm gear, she called Spenser and asked him to look for them. At BB's suggestion, she sent Requires Adjustment, Devereaux, and Naomi to Anchor 10 with Tart-Cart to retrieve a new dropship for Kilo-Five, having it immediately upgraded with the same capabilities as Tart-Cart. While at Anchor 10, they also retrieved a parcel containing ginger Parangosky had shipped to Osman for her slipspace-induced nausea. Meanwhile, Osman discovered that Mal and Vaz had been captured by the Venezian militia. Osman immediately tasked Naomi and Devereaux with the rescue mission. During the rescue mission, Osman provided tactical support from the Stanley. Devereaux piloted the Tart-Cart to rescue Vaz, while Naomi went after Mal with the new Pelican, entitled Bogof. The rescue mission was a success and Devereaux took Staffan Sentzke hostage.

They returned to Port Stanley where Sentzke was informed about the Spartan program and allowed to reunite with his daughter. Aboard the Stanley, Osman and Naomi attempted to convince Staffan to end his terrorism. Staffan agreed to hand over the Inquisitor in exchange for his daughter. However, Osman suggested to let Naomi decide if she wanted to return to her family or not, which Staffan reluctantly agreed to.

Pious Inquisitor
With Staffan's uneasy cooperation, Kilo-Five set out to retrieve the Inquisitor. However, the team soon found out that the ship had been boarded by a Kig-Yar crew, led by Shipmistress Chol Von, attempting to commandeer the ship for themselves. The Inquisitor's resident Huragok, Sometimes Sinks, was distrustful of the Kig-Yar and humans, put the ship in lockdown and only listened to Staffan. While Mal, Vaz, Naomi, and Staffan boarded the Inquisitor, Osman remained on the Port Stanley with the rest of Kilo-Five and Spenser, providing intel for her teammates aboard the Inquisitor. Staffan and BB worked with Sinks to take the ship out of lockdown. Attempting to keep diplomatic relations with the Kig-Yar, Osman had BB inform them that they were allowed to leave freely, but they refused the offer.

With Mal and Naomi pressing on the bridge, Chol Von set the ship to explode and escaped with her remaining crew. Kilo-Five escaped to their dropships and returned to Port Stanley, while Sentzke commandeered a Spirit dropship, intending to escape ONI captivity. Sentzke was not seen leaving the blast radius when the ship self-destructed and was assumed dead; unknown to Kilo-Five, he had actually survived, his Spirit having been outfitted with a miniature slipspace drive by Sometimes Sinks.

With Pious Inquisitor destroyed and the Venezian threat seemingly neutralized for the time being, Osman reported back to Parangosky and they discussed Osman's inheritance of the CINCONI's post and their future course of action with Dr. Halsey. Following this, Osman decided to read her own file, discovering that her origins were very unlike the idealized image of a happy family life she had previously imagined. She decided to visit her former teacher Alkmini Leandro in St. Malo on her birthworld of Cascade while the rest of the team were given a brief shore leave.

The Ferrets
A little less than two months later, on July 6, 2553, Rear Admiral Osman was briefly present on Gao, accompanying Blue Team in the Owl Silent Claw as they exfiltrated from the planet after Operation: JOVIAN WHISTLE. On the way off the planet, she announced the reassignment of Blue Team's three Gamma Company Spartan-IIIs and recruited Special Inspector Veta Lopis into ONI. Osman subsequently oversaw the Ferret program and more specifically the team comprising Veta Lopis, Ash-G099, Olivia-G291 and Mark-G313. On October 24, 2553, Osman supervised a training exercise between Lopis' Ferret Team and Oscar Squad in Neos Atlantis' UNSC Recreational Facility 6055-NA-A. The exercise turned into a crisis when Lopis' team was targeted by Dark Moon Enterprises and reporter Spencer Hume was killed, although the Ferret Team was able to resolve the situation to Osman's satisfaction.

Leading ONI
By March 2555, Osman had risen to the rank of Admiral and had taken Parangosky's place as head of the Office of Naval Intelligence. After it was discovered that the active installations of the Halo Array were counting down to fire in several weeks, Osman convened in Bravo-6 with several high-ranking UNSC members and scientists concerning the crisis. It was proposed that a joint UNSC-Sangheili task force be sent to Installation 00, the most likely source of the countdown, in order to prevent galactic extinction. Osman vehemently spoke against involving the Sangheili in the operation, but was overruled by Terrence Hood. Afterwards, Osman awarded Captain Annabelle Richards with the Medal of Honor, after she declined a promotion, for her success at leading the task force at the Ark.

Requiem and Infinity
On July 25, 2557, she served on the UNSC Security Council committee that debriefed John-117 following the New Phoenix Incident. The Security Council decided to tell the general public that the incident was a Covenant attack stopped by the Master Chief. During the later stages of the Requiem Campaign, she was contacted by Captain Thomas Lasky, informing her about Doctor Halsey's abduction by the Promethean Knights. She had been recommended to either keep Halsey in confinement or have her executed, but instead chose neither. Questioning the doctor's loyalties, Osman followed Parangosky's advice and ordered Lasky to execute Doctor Halsey after years of reluctance.

On March 3, 2558, Osman was on the UNSC Security Council committee that debriefed Lasky and Palmer. She berated Lasky over Halsey's escape and the complete destruction of Requiem. Osman then questioned Palmer, who defended Lasky's actions to spare him of any ramifications from Osman.

Later in May 2558, after the UNSC High Command failed to remove a Kig-Yar pirate base on the planet Ven III, Osman had Sangheili mercenary Ayit 'Sevi hired to lure the Infinity to the base. On May 8, 2558, Admiral Osman spoke with Captain Lasky to discuss the threat of a mysterious bioweapon on Ven III. Osman tasked Infinity to dispatch a two-man Spartan team and capture the Sangheili, claiming he was an associate of Jul 'Mdama, in possession of the biological agent. After Infinity destroyed the base and captured the Sangheili, ONI operatives arrived at the planet in a prowler, seized the bioweapon, and led the unrestrained Sangheili aboard the prowler—acting out the orders of Admiral Osman. After the incident, Lasky was debriefed by Osman. Lasky noted that the debriefing went surprisingly well, despite the fact that Lasky had turned a covert operation into a battle. Lasky attempted to gain more information about the operation from Osman, but she told him to drop the subject. On September 15, 2558, Osman organized Operation: ATHENA, a mission in which a team—consisting of Spartans Palmer, Gabriel Thorne, Holly Tanaka, Doctor Henry Glassman, and 'Sevi—would infiltrate Breath of Annihilation and reveal the location of the Absolute Record once 'Mdama's fleet arrived at the location. Osman briefed three UNSC officers on the mission before she tasked Lasky with overseeing the operation.

Personality and traits
Due to Admiral Parangosky's long-time influence on her, Osman is virtually an extension of the former CINCONI's will; by indoctrinating Osman and arranging her to be the new head of ONI, Parangosky ensured that her legacy and policies would continue unchanged. Before her ascension to Parangosky's place, Osman still questioned the morality of some of the actions she and Kilo-Five routinely committed, such as actively working against the Arbiter's forces, although she never failed to follow Parangosky's orders. Years later, such concerns appear to have evaporated; for example, Osman coldly ordered the assassination of Dr. Halsey, though her lack of hesitation may also have to do with her antipathy toward the doctor, likewise passed on from Parangosky. After finally reviewing her file and discovering her tragic roots, Osman was forced to reconcile this information with her hatred of Dr. Halsey. Although she truly despised the woman, she could not deny that Halsey had taken her away from a terrible situation and given her a better life than she would have otherwise had, likely saving her from a terrible fate.

As CINCONI, Osman has also inherited her predecessor's intimidating reputation; Captain Lasky, for example, was visibly nervous when contacting her about Halsey. Osman rarely acknowledges her visitors; if Osman stands up upon a visitor's arrival, the gesture is considered a genuine show of respect. Osman has an odd relationship with Fleet Admiral Lord Terrence Hood; she recognizes that Hood is wiser and has more experience than her, but Osman worries that Hood may formulate solutions to problems that she could not solve. For this reason, Osman never openly questions Hood's involvement in ONI issues.

Osman experiences unusually strong symptoms of vertigo and nausea during slipspace transitions. While she was away on missions, Parangosky had crystallized ginger regularly shipped to her as a remedy.

Trivia

 * As an admiral, Osman is the highest-ranking Spartan of any generation.
 * In the audiobooks for the Kilo-Five Trilogy, the narrator voices Osman with a Australian accent, reflecting her background at Bravo-6 in Sydney. She speaks with an American accent in Spartan Ops.
 * Çelik means "steel" in Turkish.

List of appearances

 * Halo: Glasslands
 * Halo: The Thursday War
 * ''Halo 4
 * Spartan Ops
 * Halo: Escalation
 * Halo: Mortal Dictata
 * Hunt the Truth
 * Halo: Hunters in the Dark
 * Halo: Last Light
 * Halo 5: Guardians
 * Limited Edition
 * Halo Mythos: A Guide to the Story of Halo
 * Halo: Fractures
 * A Necessary Truth
 * Rossbach's World