The T'au (also spelled Tau in older records) are a young, humanoid and technologically-advanced intelligent species native to the Eastern Fringes of the Milky Way Galaxy.
They are fighting to expand their interstellar empire and extend a philosophical concept they call the "Greater Good" (Tau'va in the T'au Lexicon) to all the intelligent species of the galaxy.
The Kroot (Krootis aviana), also designated by the Imperium as Kroot Carnivore, are a xenos species of savage humanoids who are members of the T'au Empire. The Kroot evolved from avian creatures on their homeworld of Pech.
Kroot are tall (a good half-metre taller than most Humans), their avian ancestry giving them a bird-like beak and long quills protruding from their heads like hair.
"The galaxy is ever-changing, new dangers always there. Yet the Kroot live. We survive. How?
Because we adapt faster than the galaxy, because we take from it that which will make all of us stronger.
Nothing matters to us besides the Kroot. Kin come first.
We care little for others - neither their judgement or their morals.
We consume the dead because it makes us stronger, we fight for others because their payments make us powerful.
While many races decline and rot and wither, Kroot are growing stronger. That is how we survive."
A Hunter Cadre is the Tau terminology used to indicate what the Imperium of Man would call a company of soldiers. The Tau were once a species of hunters and gatherers and the Tau who now make up what is the T'au Empire's Fire Caste were the most-skilled hunters of that ancient time. Even though the Tau are now a xenos species gifted in some areas with technology that is more advanced than that available to Mankind, the Tau Lexicon still makes use of much terminology derived from their hunter-gatherer period and companies of Tau warriors are always referred to as Hunter Cadres in the Low Gothic translation.
Pathfinders are the main scouting infantry forces for the Fire Caste of the T'au Empire. As light reconnaissance units, Pathfinder Teams are the eyes and ears of their T'au Commander in a way no T'au Drone can yet emulate.
A Pathfinder's role is not to engage the enemy, but instead to maximise the efficiency of the rest of their Hunter Cadre with their Marker Lights which designate priority enemy targets and guide the fire of their comrades.