From Halopedia, the Halo wiki
They designed and developed Project HAYABUSA, a powered combat armor similar in many ways to the MJOLNIR pioneered by Doctor Catherine Halsey, though with many differences. In late 2536 they presented to the UNSC Ordnance Committee their answer to the self-contained powered armor problem by showing HAYABUSA.
After the Human-Covenant war, RKD developed the Mirmillion and Legionnaire variants of the MJOLNIR [GEN2] armor. They offered the LEGIONNAIRE armor for licencing to smaller companies wishing to enter the competitive realm of powered armor manufacturing.
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