Michael Bradley Horrigan was born in the city of Ganymede on Mars in 2527. He hailed from a prominent political family and his parents wished that he follow in their footsteps; instead, Horrigan was determined from a young age to pursue an action-oriented career, eventually ending up as a field operative in the Office of Naval Intelligence.
Terrorist attack on Sedra
On February 7, 2556, Horrigan and his unit, led by Lieutenant Commander Jameson Locke were deployed to the Outer Colony of Sedra to investigate local terrorist activity, only to uncover a plot to unleash a bioweapon which specifically targeted humans. While patrolling the outskirts of Sedra City, the team spotted a Yonhet smuggler named Axl supplying a Sangheili Zealot with a stasis refrigerant. While Gregory Ramos apprehended Axl, Horrigan, Locke, and Alistair Estrin pursued the Sangheili. Locke chased after the Sangheili into a city access tunnel, while Horrigan and the rest of the unit headed directly to the city. Locke pursued the Zealot into a Sedran mall, where Horrigan arrived in time to watch the Sangheili jump off a ledge and activate the device, killing himself in the process. Many humans throughout the city began showing signs of infection, including operatives Jordan Gaines and Mason Hundley. The unit went to the Sedra Colonial Guard Hospital, where Horrigan and the uninfected members of his unit went through a decontamination process. After searching the tug used to transport the bioweapon to Sedra, the unit learned that the core ingredient of the weapon—an all-new element—originated from a fragment of Installation 04 in orbit around a red giant. The team discovered a second tug was traveling to the shard.
After getting the approval of Rear Admiral Goodwin, the team was forced to cooperate with the Sedran Colonial Guard to uncover the origin of the bioweapon. Taking a D81-LRT Condor to the partially functioning fragment, eleven ONI and Colonial Guard personnel traveled to Alpha Shard.
Mission to Alpha Shard
After a journey through slipspace in the Condor, the crew arrived at their destination and landed on the Halo shard's surface. Donning their powered Nightfall armor, the Horrigan and the other three ONI operators jumped out of the Condor at a significant height. After discovering the abandoned tug used by the smugglers, Horrigan discovered horse tracks nearby. The team moved to the tracks' direction and come across two smugglers—Arris Le and Haisal Wari—mining the element in a cave. The smugglers attempted to escape but Horrigan and Locke quickly incapacitated and restrained the smugglers. The group began to return to the Condor for extraction; however, while the dropship was setting down, a large number of Lekgolo appeared and began to swarm over the Condor and it flew off erratically—now controlled by the Lekgolo. As more of the Lekgolo eels appeared in large gestalt formations, the group retreated as three of the Sedrans and the horses were killed. The fast Lekgolo began to pursue the group who escaped into a narrow crevice. Locke used a special appliance to holographically camouflage their position from the aliens. However, the Lekgolo quickly sensed the cloaking unit and destroyed it. As the eels closed in on the group, Arris revealed that the Lekgolo can sense active technology and movement, prompting the group to reluctantly shut down the electronics present in their equipment. Unable to detect the humans, most of the Lekgolo left the area and the nine survivors moved out of the crevice.
After it became apparent that only two individuals would make it off Alpha Shard as their only means of escape—the smugglers' tug—could only hold two, Horrigan intended to ensure his own survival at any cost. He pushed Haisal Wari down a hill, leaving him to be eaten by the Lekgolo worms. While this allowed the group to escape, Locke scolded Horrigan for "playing God". Once it became clear Locke would not conspire with Horrigan in an effort to escape, Horrigan and Ramos mutinied against Locke and Aiken, discarding the mission to save themselves. They returned to the smugglers' tug with the captive Arris Le, intending to use the smuggler's biometric identification to activate the craft's autopilot. However, Arris escaped and Horrigan and Ramos' use of their breathers began to attract the Lekgolo to them. Horrigan activated the electronics in Ramos' backpack and incapacitated him, leaving him to be killed by the Lekgolo. Arris reached the tug first and successfully activated the biometric scanner. Horrigan shot and killed the smuggler and made a run for the tug, but the Lekgolo swarm rushing toward the now active craft caught and devoured him.
Personality and traits
Horrigan was superficially very loyal but also compulsive, arrogant and over-confident. When faced with a life-and-death situation, he cared little for the lives of others and considered his own survival paramount. In contrast to his parents' wishes, Horrigan valued the ability to rise up on the merits of his own strength and ability, not influence. In the long term, Horrigan viewed the Office of Naval Intelligence as humanity's best option for reconstruction and unity in the volatile post-Covenant War era galaxy.
He believed ONI to be superior to the Sedran Colonial Guard and was particularly vocal about his low opinion on the Sedrans during their joint mission. Horrigan insisted that the mission to Alpha Shard was ONI's mission, which resulted in Sedran Colonel Randall Aiken berating him. Horrigan was very loyal to his commanding officer Lieutenant Commander Jameson Locke; during the mission with the Sedrans, Horrigan informed Locke that he would follow the orders of Locke over those of Aiken—who had taken tactical control of the operation. Despite this, his stress and fear of being left behind eventually caused him to abandon his loyalties and mutiny against Locke.
List of appearances