While the GDF is the primary group in charge of researching and combating Erebos Spawn, Spawn show up all across Hemera, and quite frequently it falls to the local military detachments and national guard to defend an area. Most military squads do not go looking for Spawn, but they'll likely come across some sooner or later. Some squads have picked up a trick or two, and most will share tips with each other on how to effectively take out Spawn. Noting this, the GDF decided to create a new division responsible for coordinating GDF efforts with the Messembrian military. (Once things are running smoothly, they may offer their services to other nations, but for now they are working primarily with the Messembrian military.)
The ESSRT is still in its early stages, so there are a lot of kinks to work out of the system still. Most of the groundwork is being done by a squad that was brought into the GDF recently from the Messembrian military, having distinguished itself in the field. The squad members have a variety of talents: organizing intelligence reports and seeing patterns in Erebos Spawn appearances and their movements; determining effective weaponry and explosives against different types of Spawn; and experimenting with simple Geode use and teaching other soldiers in their use. This is especially important for the Spawn that are resistant to most types of attacks except magic, and although ordinary people aren't usually very skilled at magic, many can be taught a few simple tricks with Geodes that may make the difference in a battle against an Erebos Spawn. The squad leading the ESSRT efforts for the moment is still pretty low on the totem pole, and while it's likely that the division will be very useful later on, right now they're still developing procedures and working on effectiveness and efficiency.