Shas'O Kais is a leader and the featured general unit of the Tau in the Dark Crusade expansion of the Dawn of War game series.
He is the military commander of the Tau forces on Kronus in Dark Crusade. He, under the leadership of Aun'El Shi'Or'es is trying to reclaim the planet for the Tau Empire.
He is the only leader (with the exception of Gorgutz), who clearly survives if the Tau are defeated.
Should his Tau Strike Force Be victorious (non canonical ending), the Tau colony on Kronus is slowly revitalized as more Tau begin to move in from other worlds. Humans that fought against the Tau are placed in single gender re-education camps and are treated like second-class citizens. Apparently the Tau are also enacting some sort of sterilization policy to prevent human reproduction - as the human population starts to dwindle very rapidly as the Kronus colony begins to thrive.
Shas'O Kais, although new, is a poster Tau commander. He is deeply religious and devoted to the Greater Good. Unlike many other military leaders in the galaxy, he actually cares about and looks out for the welfare of his men. Yet at the same time, he will always offer his enemies, even the orks, a chance to surrender.
Using a XV22 Battlesuit like the Tau Commander Shadowsun, he is at first only equipped with a Burst Cannon in his right hand, but later in the game, at full weapon capacity, he carries a Fusion Blaster (replacing the Burst Cannon), subsequently replaced by a Plasma Rifle, a Heavy Flamer in his left hand and Missile Launchers mounted on each shoulder. He also wears Iridium armour and can be equipped with a Cloaking Field and a Jetpack and an Advanced Sensors Array to help him detect stealth units. A Shield Drone and a Gun Drone can accompany him when they are earned in the campaign.
Though there is no evidence to directly support or deny this fact, it is worth noting that he shares the same name and homeworld as the Tau protagonist from the game Fire Warrior, and may indeed be the same Kais. In the Fire Warrior book, La'Kais is also apparently driven mad by the events. But in the game, Kais is seen to be alive and well, so it can go either way, as it is indicated that La'Kais was recovering. However, it is also worth noting that "Kais" is the Tau word for "skillful", and it is itself a common name in the Fire Caste, borne by Commander Farsight for instance.