Fire Team Zulu
Fire Team Zulu was a United Nations Space Command Marine unit stationed aboard the UNSC Pillar of Autumn that actively participated in the Battle of Installation 04. They encountered Spartan John-117 about a third the way through the Assault on the Control Room, when he stepped out onto a bridge spanning a large valley.
Battle of Installation 04
The Pelican that transported Fire Team Zulu was attacked by Covenant Banshees on its descent to drop off the Fire Team. After deploying the troops, along with a Warthog, the drop ship flew out of view into the next valley where it was later found crashed into the valley wall. The crash was not witnessed by John-117, but it is assumed that it was due to the damage sustained from the Banshee attack (seen on Heroic and Legendary difficulties). Fire Team Zulu was equipped with several weapons, including multiple MA5B assault rifles, an M41 rocket launcher, and an SRS99C-S2 sniper rifle. John-117, upon meeting up with the Fire Team, helped destroy a Ghost, a couple of Shade turrets, and with a Marine manning the Warthog's turret, destroyed a nearby Wraith guarding the valley.
A Scorpion tank was present near the dropship's apparent crash site in the next valley, but it does not seem likely to have been brought in by Fire Team Zulu, as a Pelican can only lift a Scorpion or a Warthog due to the Pelican's rear hitch payload capacity and the size of the vehicles. Additionally, the Fire Team Zulu Pelican can be seen carrying a Warthog from the bridge. The tank was presumably brought in earlier by another Marine unit.
Fire Team Zulu then assisted John-117 as he fought his way through the valleys. When the Master Chief had to ascend the final main valley in order to cross a pair of bridges overlooking the valley, they did not follow because evac had become available.
List of appearances