The Loxatl (Varanus dracones) are a minor xenos species. They're a species of mercenaries with no known homeworld, and they're also distilled awesome. Basically giant murder-geckos with underslung flechette weapons which they control with their minds. Loxatl hunt in groups, and, while their vision is poor, they can taste you from kilometers away. Cool. They're also able to sense vibrations and breathe underwater, which is neat.
Loxatl are a water species and can barely see and hear out of water. Instead they use their tongues to taste the air, much like komodo dragons. The Loxatl hunt in small groups of 3, though they can form broods of 20 Loxatl. Each brood is led by a matirach. Broods will launch surprise attacks and assassinations and often go before the full assault by their employers.
They're often used by Chaos cults such as the Blood Pact and Tau as assassins because of their ridiculous speed and fine-tuned senses. Although apparently their one weakness is that they can be detected by the smell of rancid milk and crushed mint. Gross. This is assisted by their apparent resistance to las-weapons, although not enough to be immune to some good old-fashioned flashlight spam.
Idea for a Loxatl datasheet
Possible datasheet for Flechette blaster
|Flechette blaster||6||Pistol 5||4||-2||2|
Explanation: Flechette guns shoot several, fast, armor piercing rounds. The Admech flechette pistol shoots 5 rounds.