Serin Osman

Captain Serin Osman, formerly SPARTAN-019, also known as Oz, is a human senior officer of the UNSC Navy and a field agent in the Office of Naval Intelligence.

Early life
Born in 2511, Serin was abducted in 2517 as a SPARTAN-II candidate. She was given the designation Serin-019, and trained under Chief Mendez along with the rest of the Spartan-II candidates.

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

Osman did not successfully complete the augmentation process, only receiving 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 nothing skeletal. At 14 years old, the Office of Naval Intelligence took custody of her, educated her, and put her into the ONI commanders' program. They also repaired the damage done by the failed augmentation process, but the other Spartans thought her dead.

Considered as a protégé to Admiral Margaret Parangosky, the Director of Naval Intelligence, she has groomed the former Spartan for a potential future as her successor. Osman considered herself the only person who 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 never looked at the files.

Post-War
By 2553 Serin held the rank of Captain. She was hand picked by Parangosky to lead up a black operations team known as Kilo-Five, which was composed of smart AI Black Box; a civilian professor and Sangheili expert Evan Phillips; ODSTs Staff Sergeant "Mal" Geffen, Sergeant Lian Devereaux, Corporal "Vaz" Beloi; and SPARTAN-II Naomi-010 to ensure Sangheili insurgency. Using Phillips, Osman got a meeting in January with Avu Med 'Telcam, a member of the Servants of Abiding Truth on New Llanelli. She agreed to give him weapons to aid in his upcoming insurrection, but it was part of a 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 Blue Team after the Battle of Onyx. Upon arriving aboard the UNSC Port Stanley Osman transitioned the ship into Slipspace, and told Naomi-010 who she was. Naomi-010 revealed to Osman that they thought she had died.

She went on several missions aiding the Servants of Abiding Truth and continuing the insurrection against Arbiter Thel 'Vadam, and even taking Doctor Halsey into custody for "committing acts likely to aid the enemy" and meeting with Fred-104, Kelly-087 and Linda-058 and the Spartan-III's Tom-B292, Lucy-B091, Ash-G099, Mark, Olivia and Chief Mendez in ONI Research Facility Trevelyan.

List of appearances

 * Halo: Glasslands
 * Halo: The Thursday War