Fred was an ODST deployed alongside Shotty during the Battle of the Ark who, despite initially having the standard-issue Battle Rifle, was given a Fuel Rod Gun by Johnny. Johnny had picked up the Gun from a fallen Brute War Chieftain and Fred used it to its fullest extent in the battle for the first Shield Tower that protected the Citadel of the Ark. Once the first tower was clear, Fred boarded Johnny's Hornet and took down dozens of Banshees before being dropped off at the Third Tower. There, he aided the Elites in taking down the tower before spearheading the assault on the Citadel, sitting on the side of Johnny's Scorpion Tank.
Fred once again boarded Johnny's Hornet to take down two Scarabs and breach the Citadel, and was given the Hornet as a reward for his efforts. His tenacious use of the Fuel Rod Gun gained him the nickname 'Fuel Rod Fred' amongst the men of his company.
There were several reports of Fred dying during the battle, be it during the Hornet flight, in the battle for the Tower or in the destruction of the Scarabs. Where these reports come from is unknown, and the UNSC have officially erased them from record.