Locke's team

Lieutenant Commander Jameson Locke of the Office of Naval Intelligence has led his own team of field operatives on more than one occasion.

Attack on Sedra
In 2556, Locke led a remote tactical strike team consisting of six members. On February 7th, 2556, the unit was deployed to the Outer Colony of Sedra to investigate local terrorist activity, only to be caught in a terrorist plot to unleash a bioweapon which specifically targeted humans. After a Sangheili Zealot unleashed the bioweapon in Sedra City, killing or hospitalizing many of the planet's inhabitants as well as ONI agents Gaines and Hundley, the remaining members of Locke's team—Locke, Ramos, Horrigan and Estrin—were forced to cooperate with the Sedran Colonial Guard, led by Colonel Randall Aiken, despite the colonists' mistrust of the UNSC and ONI in particular.

Alpha Shard
During their search for the origin of the bioweapon, they discovered the element used in the weapon was mined on Alpha Shard, a partly functional fragment of Installation 04, a Forerunner Halo installation destroyed by John-117 years prior. They traveled to the fragment on a D81-LRT Condor, intending to capture the smugglers who obtained the element and destroy the deposits with a HAVOK nuclear warhead. However, their Condor was brought down by Lekgolo swarms present on Alpha Shard. With the survivors hunted by the Lekgolo, it became clear that the only means of escape was the smugglers', which could only hold two. Factions soon started forming within the team; after Ramos failed to convince Estrin to ally with him and discard the mission to save themselves, he let Estrin to fall to his death. Soon after, Horrigan and Ramos mutinied against Locke and proceeded back to the smugglers' tug. However, Locke and the remaining two Sedrans—Colonel Aiken and Private Macer—managed to retrieve the HAVOK warhead from the crashed Condor. With Aiken detonating the nuke and Ramos and Horrigan killed by the Lekgolo on their way to the smugglers' spacecraft, Locke and Macer were the only ones to successfully escape Alpha Shard aboard the tug.

Hunting SPARTAN-117
After John-117, the famous Master Chief, went AWOL along with his old Spartan-II unit, Blue Team, Locke—now a Spartan-IV—and a new team of Spartan-IV operatives was tasked to recover him.

2556

 * Jameson Locke
 * Gregory Ramos - KIA
 * Michael Horrigan - KIA
 * Alistair Estrin - KIA
 * Jordan Gaines - KIA
 * Mason Hundley

2558

 * Jameson Locke
 * Holly Tanaka
 * Two other Spartans

List of appearances

 * Halo: Nightfall
 * Halo 2 Anniversary
 * Halo 5: Guardians