The medical delivery drones were developed by Sky Medix before the outbreak. They are autonomous 450 millimeter-sized quads powered by arc pellets. They have been pre-programmed with automated rotating delivery parameters to deliver vaccines to the population. After the outbreak decimated the population, the medical delivery drones continued to fly their missions, dropping vaccines at their designated locations though there wasn’t anybody left to use them. They fly at a medium speed, have impact-detecting propellers and have a sophisticated object avoidance system because they fly at low altitudes. Because they run on arc pellets, the survivors hunt and catch these drones for their coveted power source.