When the existence of Seekers, and their methods, became widely known they rapidly earned the unofficial name of ‘Harbingers’ as doom and destruction followed in their wake. Initial encounters between the Free Trade Union and the first Seekers were disastrous for the FTU, who lost much of their pre-war fighting strength discovering just what role this creature plays within the Swarm.
What they learned, and fortunately disseminated to other forces when the Alliance was formed, is that Seekers play a dual role equivalent to that of scouts and officers. When performing a scouting role the Seeker operates alone. They seem to be blind, as far as we understand it, but are attracted to active technology such as lights or radios. What makes Seekers so dangerous is that by some unknown means their deaths inevitably result in all other Swarm creatures for miles around converging on the location of the Seekers corpse, often resulting in far heavier losses than the Seeker itself would be responsible for. As such, standard alliance doctrine with solitary Seekers was to hide and wait for it to pass by. Seekers seem oblivious to people unless they make themselves obvious or attack the Seeker, and while they will be very interested in energy sources they will eventually lose interest.
The second function of Seekers is perhaps more dangerous. Seekers in the presence of BC’s seem to dramatically increase their intelligence. Reports of tactics, ambushes, and feints from BC’s were initially dismissed by the Alliance as battlefield confusion. But after the Fall of Shacksville, the Alliance was forced to concede that Seekers operate as some sort of mobile mind, vastly increasing the capabilities of its accompanying BC’s. No useful tactic has been developed for dealing with this combination other than gratuitous use of force.