Tanith is a Dead World, the former homeworld of the famed Tanith First and Only Astra Militarum regiment, whose population was exterminated by the orbital bombardment of a Chaos Warfleet.
Tanith was formerly a heavily-forested Imperial Hive World / Agri-World located in the Sabbat Worlds Sector, a cluster of planets in the Segmentum Pacificus that was under constant assault by the Forces of Chaos.
History:
Due to its destruction, much of the earliest history of Tanith has been lost to Imperial records, but fragmented accounts speak of a time when Tanith was ruled by a planetary monarchy known as the Huhlhwch Dynasty. However, its rule came to end when the monarchy was brought low by the Nalsheen, the wood-warriors of ancient Tanith lore who fought using only spear-staves tipped with single-edged, silver blades. They united Tanith and overthrew the nobility and the feudal order they upheld, paving the way for the later, democratically-governed Tanith city-states.
During the Sabbat Worlds Crusade, following the death of the Warmaster Slaydo, a splinter Chaos Warfleet slipped past the picket fleet set up by the Imperial Navy due to the newly-appointed Warmaster Macaroth's change of tactics. This small Chaos fleet attacked and conquered six worlds, one of which was Tanith.
The Chaos armada bombarded Tanith from orbit, and deployed ground troops to kill whatever the heavy orbital guns had missed. The forests of Tanith burned to ash under the crippling firepower of the Chaos warfleet. It is not clear if Tanith had any functioning planetary defence artillery batteries, or if the Tanith Militia was able to fight back against the invaders.
Colonel-Commissar Ibram Gaunt was one of the last people to leave the planet before its demise, and was saved by a youth named Brin Milo, whom he took with him in gratitude. Milo confirmed that he was the only civilian to leave Tanith alive, having been too young to join the Imperial Guard.
Government:
The hive cities of Tanith were great stone bastions. The capital city of Tanith -- known as Tanith Magna -- was no exception, and was known to be surrounded by a giant wall, presumably to keep the nalwood trees from moving into the city. The world was governed from the capital by an Imperial Planetary Governor, known locally as an "Elector," and the main governmental building appeared to be the Assembly (although Rawne also mentioned a place called the "Elector's Palace" when hypnotised on Monthax).
It is unclear as to whether or not the Elector was elected as the title sounds, or if it is an inherited position like a monarch or other aristocrat. Tanith was administratively and culturally into counties, among which were Counties Pryze and Cuhulic. This system of organisation was very similar to that found among the Old Earth polities of Ireland and Scotland, whose cultures were similar to that of the people of Tanith.
Each city on Tanith had a Militia, from which a number of members of the Tanith First and Only were drafted into the Astra Militarum.
Flora and Fauna:
The planet was covered in dense forests of mobile trees known as Nalwoods -- these creatures were actually a type of photosynthetic animal-plant hybrid, while their wood was the world's primary export. The primary industry was the harvesting of seasoned Nalwood timbers and a large wood carving industry that created pieces of beautiful woodwork that were highly prized across the Imperium of Man.
This wood became even more prized and valuable after the planet's destruction. The Nalwoods themselves were capable of completely uprooting and moving to new locations, and were known to migrate from place to place following the seasons and the moving sun. 4
The moving forests made any roads or paths through the trees quickly obsolete, and for this reason, the Tanith have developed an almost preternatural sense of direction, bred into them by adapting to this environment. Tanith had at least one major sea or ocean, and polar ice caps were present all year round.
