Just remembered seeing this type of unit inside a show I watched and thought something similar to it would fit in the Dark Potential universe; not sure of a specific faction but I'm sure it would fit somewhere.
The basic idea is that the thing is like one of those giant mechs you see all the time, except compacted into human size and just as dangerous. Just using this as a source of inspiration of course, it would be nice to see how the community can edit the basic designs.
[EDIT] Also found a design that might suit the look of the game, I remembered watching it in a movie a long time ago and liked the look quite a bit.
[EDIT...Again] For the Reclaimers I felt that since they were unused for Earth's environment then that would mean they can't handle prolonged fighting. Because they rely on their exo-suits to carry out their tasks on Earth they can't afford to stay in long firefights, longer fights mean the more risk for their suit to take heavy damage. So my basic idea was that the Reclaimers would be a more melee and steath faction, getting as close to the enemy as they can, while doing heavy close combat damage. Thay would also be quite fast due to their exo-suits and their general slim frames; however very fragile as well and vulnerable to mass ranged attacks.
The basic look I was going for them was slim, flexible, and the ability to quickly go in and out of stealth, mainly hit and run tactics. The faceless mask design just seemed to go with their background, it gave them a sort of humanoid appearance yet at the same time making them seem alien (In the difference kind of way, not the literal outer space kind) to the rest of the human factions. Going with their designs the main technology they would deploy are stealth, as well as tech that disorients opponents, such as anti gravity bombs or emp weapons that damage enemy helmet sensors.
Also I for some odd reason can imagine the faction melding in and out of shadows, don't ask me why, but I feel like it would really match their style. The basic look going by the current background gave me a sort of feudal japan type of feel. With the soldiers who undergone muscle training as the elite units, with a kind of cyborb samurai look, and the less muscular placed in the stealth role, looking like the pictures above.