Achaemenes was the king of the Ahura during the first war against Ahriman.
He fled into the desert, but when the city fell, he return to liberate it from Ahriman, empowered by Ormazd. He refused to be buried in the city for he felt shamed for allowing the city to fall. Therefore, he was buried in secret and later found by pilgrims and moved to a tomb in the Underground Palace.
Achaemenes is the name of the legendary founder of the first Persian dynasty.