As Diego Navarro was on the run from the advancing Aurelian forces, during the Aurelian War, he escaped to Archelon Fortress with the remaining prototypes of Fenrir. Aurelia performed a short island-hopping technique to quell Leasath forces, including the High-Powered Microwave weapon.
The HPM was located at Cobalt Cave where it was being transported to Archelon Fortress via container ships. Gryphus Squadron was deployed to destroy these ships before they could escape the area. The squadron also destroyed warehouses filled with chemicals. The weapon was ultimately destroyed and the HPM was no longer a threat. 
However, this allowed the Leasath Air Force's elite Alect Squadron to cross the Danern Straits and reach Archelon Fortress in order to pilot the Fenrir prototypes, thus making the aircraft even more of a threat to deal with.
The HPM works as a standard heatseeking weapon that ignites fuel caught in between two opposing "plasma spheres," one emitted by a Fenrir and the other emitted by Archelon Fortress. An overlapping effect is created, which results in the plasma spheres.
The weapon was manufactured and created in Cobalt Cave, where satellites were placed to add a tracking capability to the HPM to make it easier to find and destroy aircraft. An electrical plant near Archelon Fortress powers the HPM (along with Fenrir's DOS system).
- If the player escapes a plasma sphere before their plane is destroyed, their engine's temperature begins to stabilize. However, this wouldn't be the case in real life; the electronics within the plane, along with the engine itself, would be structurally damaged by the sudden, intense heat. The plane would retain some internal damage after escaping the sphere.