The Harvester is a Squad of tough Automated Sentry Guns
Offense: These are deadly to infantry and are even useful against the dreaded Hastatus Snipers and Primes. They are pretty durable so can be used as cannon fodder to protect other units since they come in a group of three. They have very short range but a high rate of fire so with three they can also kill low armor recon units.
Defense: They are vulnerable to just about anything with armor like a tank or units with great firepower and a high rate of fire. A tank with a high rate of fire like the Great Sickle or Reaping Truth are very effective as a counter. Also something with an insane rate of fire like the Sagittarius or Raynin's Defense make quick work of these. Longer range units work as well and can take these out before they become a threat.
Where to Obtain Edit
They were a reward in an event but can now be obtained from Gold or Elite chests
The Harvester is the cheapest variant