the headhunters kill teams are the chosen reavers of the loyalist piratical chapter of the xenostalkers, the xenostalkers are elité in stealth and in rapid jump pack assited assaults, a large number of their ranks are psykers and for these kill teams they employ only psykers to use their powers for stealth,movement and devastating bolts of psychic prowess.this chapter employs xenos technology and also enslave or exploit their species, like the pariah-tech tyranids or the . the xenostalkers reside in the ghoul stars, they defeated the thexians in their homeworlds of the Bloodmoons of Thex Prime without the imperium knowing by involving part of hive fleet kraken and after the tyranid devastated the moons they got annihilated by a orbital strike of virus bombs, but managed to capture and enslave alot of the tyranids with old pariah-tech and nullstone material to sever the connection with the hive mind and be radio-controlled, now they reside in the blood moons and are their main stronghold and there they have a vault of ancient archeotech that their techmarines managed to re-invent, they are the most important line of defense against the outer xenos threat.