Human soldiers have provided the backbone of the Aquarian ground-forces and marine infantry units for millennia; from standard foot soldiers with basic gear in the Federal Reserve Forces in the Old Federal Era to the genetically-enhanced power-armour-clad super soldiers of the Imperial Planetary Forces in the Imperial Era. Despite all the enhancements and alterations designed to augment them; one thing has remained consistent - the human element. The Director places great emphasis on preserving the humanity of the Armed Forces of the Imperial States, but that doesn't rule out advanced automation projects aimed at providing highly flexibly robotic infantry units, such as the Enhanced Mobility Semi-Autonomous Heavy Infantry project, or EMSAHI, initiated by the Imperial Planetary Forces Research & development institute in the early cycles of the 46th century.
Directorship-level approval was granted to the project due to the pressing need for more flexible and autonomous drone systems with enhanced (aerial) mobility for operating in the increasingly important theatre of the Eridonian Ruins. The nature of the ruins prevented more 'traditional' bipedal infantry (including human soldiers) from operating effectively, so a new type of infantry was required - the EMSAHI project was designed to bridge the gap between Heavy Infantry units and Autonomous Combat Drones.
The project was given basic requirements for the core design phase;
Autonomous Infantry Units must have locally human-overridable control systems;
I.e, 'pilotable', and remotely operatable by humans.
Requirement for Dynamic Modular Weapons System allowing highly versatile, configurable weapons and systems deployment in line with expectations from infantry-held weapons capability.
Aerial Mobility System: units must be equipped with aerial propulsion systems to navigate otherwise impassable terrain and obstacles.
Smaller and lighter than existing Power Armour Units.
Although the EMSAHI project was primarily designed to create Infantry units able to operate in the Eridonian Ruins, the need for such an Infantry Unit was recognised in other areas of Imperial Planetary Forces and Marine Corps doctrine, for example operating in the ruins of city-planets or within large space installations.
By 4505 A.D, the EMSAHI project had yielded prototypes that were rolled out the cycle later forming the first "Scorpion" Unit deployed to the Eridonian Ruins for trials in 4521 A.D.