Kaitlyn-B237 (Born Kaitlyn Madson) was born on February 14, 2531, on the colony world of New Constantinople in the Zeta-Byzantium system. Not much of her childhood is known prior to New Constantinople being attacked in early 2537, where she would be orphaned. Following the Battle of New Constantinople, Kaitlyn was evacuated to Cygnus, where she, along with other children, were placed into the care of the planet's system of orphanages. It was during this time that Kaitlyn became known as a bully amongst the other children, attacking others who had displeased her.
In late 2537, Kaitlyn joined the Spartan-III program as a part of Beta company, where she would excel due to her aggression and understanding of tactics. At first, Kaitlyn would mistreat her fellow trainees, much in the same way that she had treated her fellow orphans on Cygnus. However, upon learning that the preceding Alpha Company, had been present during the Battle of New Constantinople, her ire shifted to Alpha Company. Reasoning that they were to blame for the deaths of her family, coming to viewing them as inferior soldiers. A point which would be reinforced after she later learned of how Alpha Company had broken cohesion during Operation: PROMETHEUS resulting in the entire force being annihilated to a man.
By 2544, Kaitlyn graduated from the program as the leader of Gustav Team and of Commando Group Beta, seeing initial combat during the Siege of the Atlas moons later that year. In 2546, Kaitlyn would come into contact with Alpha company's Commando Group Alpha. Encountering her rival Jake-A384, the XO of the group, who began to undermine Kaitlyn's hold of fear over the Beta's. Kaitlyn tried to minimize contact with her Alpha contemporary's, whilst attempting to have Jake disciplined by his superior, Carter-A259. This was due to the level of respect between the two, the latter regarding the formers social skills to be an asset, despite them being sometimes grating. However, the damage was done, as Chrissie-B278, a Spartan who had always disagreed with Kaitlyn's opinion, due to owing her life not just to Alpha company, but Jake and his Grizzly team specifically. This began to erode Kaitlyn's ability to bully her subordinates into line, arguing with her on the subject of the Alpha's, willingly taking verbal harassment in return.
In 2547, Kaitlyn was sent to the planet of Saint-Denis, one of the worst battles of the war up to that point, resulting in the deaths of six Beta Spartans and six Alphas. Kaitlyn and the remains of Commando Group Beta was merged with the depleted Commando Group Alpha forming Special Warfare Group Three (SpecWarfare Group 3). Resulting in her promotion to the rank of Lieutenant-Commander, taking the position of XO field commander, in addition to taking command of one of the cross-company teams, designated Red Team. This move pleased her as it made her superior to Jake in addition to Chrissie, whose new teams she endeavoured to have filled by Beta's whom she considered 'trouble'. This included her former teammate, Gwen-B161, who had stood up to her during Saint-Denis. Kaitlyn now used her new power to have them assigned the more difficult tasks, leaving them isolated from the rest of the unit and at a higher chance of injury. After the merger Kaitlyn's distaste of Alpha's subsided, being forced to admit their combat skill and prowess. Instead focusing her disdain on Jake, primarily due to his personality, in addition to his actions that had obliterated her control over the Beta's.
Prior to 2552, Kaitlyn engineered events to have Kat-B320 promoted to the rank of Lieutenant-Commander ostensibly in the event of Carter's death leaving Noble Team without a leader. However, her ulterior motive was to ensure that Jake was kept out of a position of command, a prospect that she was determined to prevent. This nearly came to nought in the aftermath of the Battle of Fumirole, which had resulted in the death of Thom-A293 and the loss of Kat's right arm, with Carter and the rest of Noble being pulled from action for the next few months. Due to the casualties at Fumirole, Kaitlyn temporarily took over command of the unit, with Jake acting as XO, though the pair were kept apart. The latter with liaising with ONI Agent Codename: EXCALIBUR, whilst the former dealt with the issues that had arisen following the battle.
During the Battle of Reach, Kaitlyn and her Red team initially focused on offensive actions against the initial Covenant invasion until after Operation: UPPERCUT, which resulted in her team being retasked to defensive operations, primarily covering civilian evacuations. By August 30, Kaitlyn and her Team working joint operations with Faith-A199's Gauntlet Team and Victoria-B346's Echo Team, and having picked up the lone Noble Six, were retreating to rally point Omega. Planning to await an evacuation along with remaining UNSC forces in the area, however, during the retreat, the group was forced to cross a bridge under Covenant fire. Red Team and Noble Six crossed first to set demolition charges, with Gauntlet and Echo following piecemeal, until only Faith and Echo Four, Quinn-A098 remained on the far side. At this point, a stray plasma shot caused the charges to detonate early, cutting off the pairs retreat, unwilling to risk further casualties, Kaitlyn withdrew the remaining Spartan's, leaving the pair to what was assumed to be certain death.
Arriving at Rally Point Omega, the Spartan's and surviving UNSC forces were assaulted by hordes of Covenant, killing the UNSC forces early on, before whittling down the Spartan's. Kaitlyn, concerned at their position, attempted to summon aid, finding only Jake's Brimstone Team, which had been sent to recover the remaining Spartans for evacuation, though was too far away to assist in time. Kaitlyn, concerned at their position, attempted to summon aid, finding only Jake's Brimstone Team, which had been sent to recover the remaining Spartans for evacuation, though was too far away to assist in time. Alone, Kaitlyn, begged for Jake's help, for the first time using his name. Before he could respond, Kaitlyn was impaled by an energy sword, eviscerating her internal organs. Kaitlyn died where she lay, with only the voice of Jake, begging her to respond.