Harvesters are massive cylindrical structures employed by the Frontier Militia (and presumably the IMC), utilised for the extraction of minerals from a given planet's surface. The mechanism(s) through which this is achieved, or how materials are then transported into orbit is currently unknown. Harvesters have additionally been seen in areas such as Angel City, Training Ground Whitehead and Airbase Sierra, alongside other areas not ostensibly rich in resources for extraction. What strategic value these sites hold for harvesting is a mystery.
Harvesters are only found in the Frontier Defense game mode, where they are the central objective for Militia Pilots to defend against incoming waves of enemy troops, with the faction depending on the game; Titanfall has IMC forces attacking the harvester, while Titanfall 2 instead switches this to the Remnant fleet. Much like Titans in the first game, Harvesters are equipped with two layers of health; the first, an energy shield capable of taking hits to preserve the base health of the structure, and recharge after a short period of no damage. The second is the armor itself, non-replenishing health that is permanently gone once removed. In both games, bonuses are usually given for defending the harvester without letting its actual health take damage.