It is designated a Xenos World by the Imperium. However, they were forced to pull back in light of the advances of Hive Fleet Behemoth. When the Imperium returned following the warp storms, they attempted to conquer the Tau empire, and were successful in conquering quite a few planets. When the Imperium first arrived in the vicinity of T'au, it was a feral world with primitive people scraping a living off of the ground. Only six thousand years later, the Tau Empire spanned 300 light years. During this time, the world was plagued in a series of violence and turbulence that were dubbed the Mont'au and only ended with the arrival of the mysterious Ethereals who unified the planet shortly after. The T'au planet itself was surrounded by vast warp storms, cutting off the entire region. Planet was scheduled for cleaning and re-colonisation but the despatched for its cleaning Imperial Navy fleet was destroyed in a violent and freak warp storm. The planet was discovered by the Imperium at 789.M35 by the Land's vison, an explorator vessel of the Adeptus Mechanicus.

T'au is home to a large moon known as Lu'val, which was the first off-world colony of the Tau Empire in 533. At the centre of this city appears to be a heavily defended fortress, possibly the heart of the Tau empire, the high council of the Ethereals. No humans have ever walked on the streets of the capital, located on the equator, and Imperial scans are blocked by some Tau technology. Cities rise into the sky, covered in white marble, in stark contrast to the Hives of the Imperium. The little arable land is covered with efficiently run collective farms managed by the Earth Caste.

The planet itself is a hot, dry, arid world primarily covered in Savannah and scattered mountain ranges.

Warhammer new world colonies