They use primitive weapons and wear tribal masks. They perform meaningless rituals. They are alien in origin, but we are on an alien planet…minus the prison station. They have imperfect cloaking which would be extremely powerful at range but instead are seemingly forced into close range combat only. They only seemingly randomly fire some kind of stun explosive thing. Any buildings they occupy look like ancient ruins.
As far as I am concerned they are primitive native aliens who stole higher tech like cloaking from some other aliens.