The Drones are the most common enemies you encounter in the game. They always come in bunches and tend to come out of emergence holes. They aren’t the strongest or the weakest member of the Locust Horde, instead they are well balanced and can take on any human that is in their way. They are normally armed with Hammerburst assault rifles, but can also be seen wielding Lancers.
Most weapons can make fairly quick work of these enemies. Your best bet is to hit them from medium range with the Lancer to conserve ammo for more powerful weapons. If they try to jump over your cover or get close, you can use the Lancer’s chainsaw to kill them. Or, if you prefer you can use the shotgun to make quick work of them.