The time period around 2479 of Axel history saw a lot of exceptions and unusual developments. While some of this can be blamed on the Earth's crash weapons development program, the Lunar forces on the moon were also responsible for a lot of unusual designs that pushed the boundries of what is considered an Axel. The OUS-10, for example, seems to have more in common with a space fighter operationally than a true ground fighting Axel.
The OUS-10 was an outgrowth of the OU-8's development, with the mindset of creating an 'interceptor' Axel that could stop UEPC forces from actually landing on the moon (even though in the few times where they did, OU-8s were successful in fighting them off. The intent was to give more manuvering thrusters and larger rocket engines to increase the forward delta-V of the intended unit.
With the low-gravity environment of the moon, the resulting unit spent more time 'airborne' than actually bouncing across the lunar surface as its OU-8 counterpart typically did. The resulting experimental unit was termed the OUS (Space) 10 unit, and was frequently deployed at higher lunar altitudes to intercept Earth probes and skirmishing units. Kriggas are also very effective against Earth carriers, which due to crew requirements are slow and ungainly.
Krigga units have no onboard armaments, either relying on light Axel armaments in their hands or mounted weapons saddles hooked on to the torso.