Overseers are like Guardian drones, but with much thicker armor and better weapons. They are rarely seen without a Hive Queen. Overseers will escort a Queen in sets of two and can be very dangerous. They also can be found in Hive Skirmishes, mostly in large, in critical escorting the Queen, or in central, where the Leviathan is found. There these bots renamed to their respective hives name (Siepos, Milanar and Prosus, or with the word "Stronghold"after it if in a central skirmish).
The K-3 Overseer patrols alongside a queen or in sectors with transports. It mounts positrons and a Gatling Cannon MkII. Heavy armor protects these bots. Since they are always with something to protect, they will not attack you until you prove hostile, but when they do attack, they will not be alone. Overseer bots are not common enough to use for leveling purposes.