Mark III exoskeleton
From Halopedia, the Halo wiki
The Mark III exoskeleton is essential a strength-enhancing suit for a human operator, with applications in many fields due to their ease-of-use and load-bearing capacity. The initial Mark III exoskeleton prototypes featured neural interface controls, in addition to a sealed armoured canopy for the operator, noted as visually reminiscent of later EVA-class Mjolnir helmets.
The Mark III line of prototype armoured exoskeletons was initially launched in 2510. It is likely that it was a successor to the earlier Mark I exoskeleton. However, the Mark III line became defunct quickly after its launch, with the Office of Naval Intelligence scrapping their plans for the exoskeleton and pursuing the fledgling Project: MJOLNIR instead.
In 2513, a Project: HRUNTING research team at Weapons Research Facility T12A on Algolis evaluated the abandoned Mark III line and made many of their own breakthroughs. These culminated in the production of a new variant, now called HRUNTING Mark III [B] or, more informally, the "Cyclops". After this variant was created, the original exoskeleton was retroactively given the name Mark III [A].[Note 1]
Mark III [A1] Peacekeeper
A specialised variant of the Mark III [A] exoskeleton, designed for law enforcement SWAT teams. They were often equipped with a large riot shield and a low-pressure autocannon that fired riot-control munitions. However, most were destroyed after being pressed into active combat duty.
HRUNTING Mark III [B] Cyclops
A significantly improved variant of the Mark III exoskeleton, nicknamed the Cyclops, produced by Project: HRUNTING after evaluating the then-defunct original Mark III line. This variant was originally designed for non-combat roles within the military, such as dock work, but has also been fielded in combat situations, for repair work and in even rarer cases, in anti-fortification roles.
Though it has never been seen in any visual media, the description of the original Mark III [A] exoskeleton given by Halo Waypoint bears a striking resemblence to early Halo Wars concept art of the HRUNTING Mark III [B] Cyclops, suggesting that the concept art represents the canonical visual appearance of the Mark III [A].
Some sources, such as a Halo Waypoint video series, conflate this Mark III exoskeleton with MJOLNIR Mark III. However, this Mark III exoskeleton predates Project: MJOLNIR, and so this is treated as a mistake.