Source: Bestiary 4, pg(s). 264
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The original trox on Nchak were eight-legged arachnids, though the variant found outside Nchak are arthropodal humanoids, their two central sets of limbs atrophied, their muscle allocated to their legs, upper arms and fleshy tail; their natural exoskeletons enhanced and their mandibles expanded into bony scythes.
The trox were originally a peaceful race of burrowers. Long ago, an incarnation of Nchak's ruling Forever Queen selected a contingent of trox for the task of interplanetary expansion. The explorers were magically altered into their humanoid for, then divided and ensconced in the centre of moons, which were then ejected out of Liavara's orbit.
One of these ships reached Golarion and dug down to the Darklands, near a duergar city. The duergar wasted no time in enslaving the emerging trox, and bred them for strength and brutality. After a few generations, the hulking trox were bound to their masters by fear and pain, memories of their ancestral home fading, although over time a few isolated groups have escaped captivity. Several clans were able to reach the surface world, whose residents were just as eager to enslave them.