"The T'au arrive at your world, with a fleet, tanks, attack craft, fire warriors and battle suits, and they ask if you want to join in their quest to achieve the Greater Good. Well, that’s the way I think it happened with the galgs. The galgs were clever enough to say yes, but there are some records that show what happens to those worlds who say no. Sooner or later they either say yes, with their cities burning and their soldiers rotting in their open graves, or are in no position to say anything at all."
- — Inquisitor Oriel
The T'au conquered the Galg homeworld several terran centuries before the end of the 41st Millennium through their usual method of deploying a full invasion fleet in orbit and inviting the Galgs to join the Greater Good, to which they promptly agreed.
Since then the Galgs have served the T'au Empire, and some of them operate as auxilliary troops alongside the Fire Caste.
Anatomy and Physiology
Galgs are multi-limbed creatures with the shape of amorphous blobs. They have no heads, but clusters of waving eye-like organs, and a set of six tentacle limbs which serve them as both arms and legs.
Galgs are not particularly warlike, nor highly advanced technologically.
- Kill Team (Novel) by Gav Thorpe, Ch. 6