The Imperial Tithe is the mandatory tribute that every world of the Imperium must render unto Holy Terra, the price of the Emperor's protection and the lifeblood of a galaxy-spanning empire. Assessed by the Adeptus Administratum, the Tithe may take the form of raw materials, manufactured goods, promethium, foodstuffs, or the most precious commodity of all: living men and women conscripted into the Emperor's armies.
Tithe grades are levied according to a world's productivity and resources, ranging from the token contributions of struggling frontier colonies to the staggering exactions demanded of hive worlds and forge worlds. A planet that fails to meet its tithe risks censure, invasion, or worse, for the Imperium regards the withholding of tribute as a step toward rebellion.
Through the endless flow of the Tithe, regiments of the Astra Militarum are raised, fleets are fuelled, and the insatiable machine of the Imperium is sustained. It is a burden borne by untold trillions, the true and terrible cost of belonging to mankind's domain.