iirc, the SARP currently has a rule prohibiting the creation of additional humanoid races (and tbh, they remind me of the Reavers [firefly]/Rippers [Tankgirl]/ Early Klingons [Startrek], etc).
You could get around this by turning them into a criminal operation (
Something about it reminds me of the Chinese and Japanese syndicates like the Triads and the Yakuza, albeit pushed to an extreme and reckless edge ) and a clan that revises some ancient mythos (I've not seen this before in mainstream entertainment with the exception of
The Red Dragon Crime Syndicate which evolved from
"The Order" in Cowboy Bebop which was never properly explored).
If you got worried about angry empires wanting to wipe them out, you could beef up the threat value a notch by having them use weapons from the black market and having them use guerilla tactics like hit&run and ambush so they lure in vessels, cripple them then pillage them. (
Ideal targets range from light military vessels to isolated armor/fighter groups who've lost their commanding vessel, cargo vessels and munitions transports).
In conjunction, drop in some nomadic behavior so it is especially difficult to find them unless they're looking for you.
This would probably secure them in the SARP as a tool for GMs to use (either way, I think they'll be used to create problems for player characters to solve creatively in interesting ways, which is awesome).
Regardless, awesome stuff.
Keep up the good work.