There can be no doubt that the UnB-140 Onslaught is one of the longest serving, if not the longest serving, models of combat zeoform in existence. Its core design can be definitively traced back two and a half centuries. Entire treatises have been crafted around the preexistence of Onslaught components in data caches going even further back than that.

Indeed some consider it the primogenitor of all modern bipedal zeoform designs, a romantic flight of fancy that ignores known facts in favor of a hyperbolic fairy tale. 

There can be little doubt of the UnB-140's longevity and the durability of a solid core design. Even so, considerable resources are expended keeping the Onslaught compatible with new developments. The most recent change is easy to spot even for a layperson, as the old flat-aspect Neutronium protective plating has been replaced with the kind of multi-layer armor shells now popular in GuardCorps circles.

Nonetheless, the power supply, frame, and actuator layout are readily identifiable as those used 250 years ago. Why? Advocates might respond “because it still works.”

It can be said that Heavy Assault Zeoforms require little development conceptually. They are used for breaking enemy strongpoints, or simply breaking the enemy in general. An Onslaught Heavy Assault Zeoform handsomely fulfills this role, combining ranged and melee power with layered defenses and state-of-the-art repair systems.

Continually updated, its highly advanced z-control systems mean that only the most talented or experienced GuardCorps pilots can use them, and even then after months of hands-on training. The size and weight of Heavy Assault-class zeoforms means they are difficult to transport and maintain, and thus they are normally only deployed to the hottest fire zones.