Created by a joint Free Worlds League/Word of Blake research team, the Achileus was developed in response to the Federated Commonwealth's innovative (but fatally flawed) Infiltrator BattleArmor design. The team's goal was to design a mass-manufactured light BattleArmor suit that combined a full-sized arsenal with a comprehensive electronic stealth system.

         Using the Word of Blake's Tornado Power Armor (Light) suit as a model, the research team spent long months redesigning the suit's stealth systems to accomodate additional armor and weaponry while maintaining its low electromagnetic signature. Unlike the Tornado, the Achileus features armor-composite sheaths to contain and protect its layers of myomer musculature. The Achileus also features integral mounts for jump jets and a gyro-stabilized gun mount in the right arm. These features add vital protection, mobility and firepower, but make it increasingly difficult to effectively mask the unit's presence on the battlefield.
         Success was ultimately achieved based on data intercepted by Word of Blake ROM while being transmitted from the NAIS to Defiance Industries. The data provided a new formula for composite armor. Using the formula, designers were able to provide the Achileus with the armor-protection standard set by the FWLM. The resulting prototype proved to be one of the most effective BattleArmor designs produced in the Inner Sphere at the time and it continues to be competitive to this day.
         In addition to a right arm-mounted anti-BattleMech weapon, the Achileus mounts a single anti-personnel weapon, usually an SMG, on the left arm just above the wrist. Both the suit's arms end in fully functional manipulator hands. These provide the wearer with a greater degree of dexterity when lifting and manipulating equipment than offered by standard BattleArmor suits. This feature reduces the amount of armor the suit can carry-thus reducing the design's effectivness in melee combat-but the extra dexterity can be very useful during infiltration and scouting missions.

         The Achileus is deployed throughout the Free Worlds League, where it has proven to be an effective combatant against multiple invasions over the years.