Genestealer Familiar

A Genestealer Familiar is a type of small Genestealer created from the raw psychic energy produced by a Genestealer Patriarch or Magus that manifests in realspace as a living organism.

Should a Patriarch or Magus be powerful enough, the psychic shadow that gathers around them will grow darker and thicker until it begins to coalesce. This ever-shrinking miasma hardens into a many-limbed form -- a Familiar. When the Familiar is fully manifested, it skitters from its hiding place and runs to the heel of the xenoform that unconsciously created it.

From that point on, it is as much a part of them as any hand or claw. Small and nimble, such a creature is an excellent spy, able to scuttle through the tightest crawlspaces and report back to the cult's leader through the potent psychic bond that links them.

Should its master be threatened by a physical attack, the Familiar will leap up to claw at the attacker's eyes and throat, gouging its small but iron-hard talons into vulnerable flesh so the Familiar's creator can deliver the coup de grace.