Fireteam Lancer is a unit consisting of fourth-generation augmented soldiers, or Spartan-IVs. Lancer was one of the known Spartan contingent units aboard the UNSC Infinity during their second mission to Requiem in early 2558.
Fireteam Lancer was assigned to the UNSC Infinity at some point prior to the Second Battle of Requiem. Lancer fought on the surface of the Shield World during the battle, and was one of the few teams that was on board the Infinity when the ship was attacked by Promethean and Jul 'Mdama's Covenant forces. Lancer then proceeded to nearly single-handedly retake Translight Deck 19-7 from enemy forces, securing the Infinity in conjunction with a handful of Spartan and Marine fireteams.
In the following days, the UNSC redoubled its efforts to oust Covenant forces from Requiem. During an operation in REQ//3490-9299, Lancer encountered heavily entrenched Covenant forces and requested backup. This came in the form of Fireteam Crimson, who aided Lancer in storming Covenant positions. Upon reaching a large Forerunner structure deep within the site's cave system, Lancer and Crimson found the survivors of Fireteam Switchback, who had been assumed as KIA for several days. After freeing the Spartans, Lancer, Crimson and Switchback fell back for Pelican evac.
- Like most Spartan/Marine allies in Spartan Ops missions, all members of Fireteam Lancer can be killed in-game. However, they are the only Fireteam to be mentioned by name later in the season, which may indicate that canonically, the fireteam survived the mission in which they appear.