The UNSC 3rd Roving line is a mobile fleet. Unlike most other fleet the 3rd Roving Line is'nt assigned to a specific system, instead it is in charge of protecting UNSC's territory. As a roving line it also called for emergency reinforcement in case of an planetary invasion. The concept of an roving line came in the mind of the fleetcom right after the Human Covenant war. At this time, the Highcom was curious to know how to improve the unsc fleet versus the remanning covenant fleet. They were first impressive by the reccord of the UNSC 14th Nomad Fleet and the 1st Naval Armada wich were the first units to act has a roving line. The decision was taken withing the rearming program for the UNSCDF would create a serie of news fleets to act as rovings lines. in early 2594 10 rovings line were al