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Exalted: The Autochthonians is a supplement for Exalted covering the Primordial Autochthon and the human civilizations living within him. It expands on material previously introduced in Time of Tumult to provide a fuller picture of the Autochthonians and the Alchemical Exalted.

Unlike other Exalted Fatsplats, EtAu devotes four chapters to Autochthonia and Alchemical Exalted, and then provides three alternate scenarios expanding on the Locust Crusade originally outlined in Time of Tumult. In one of these scenarios, the Locust Crusade expands to an all out war with the Realm, in another, the players race to provide souls to Autochthon before the Primordial dies, and in the third the Autochthonians fall victim to the Great Contagion. It is the first Fatsplat to cover creatures not mentioned in the Exalted Rulebook, and consequently provides a variety of optional scenarios.