The Cult of Kosmos was a deistic cult in ancient Greece which worshiped Kosmos, the embodiment of harmony and order in their belief system. The cult was founded in the 6th century BC by disaffected members of Pythagoras' Cult of Hermes, and the cult was known for its rejection of Hellenic polytheism in favor of deism. The cult also sought to establish an orderly and unified Greek nation which would be a rational and developing society without violence, and its views were inherently populist. The means of achieving this ideal state, however, were through a controlled war which would create a clean slate on which to establish this new society.
The Cult supported Xerxes I of Persia during the Persian invasions of Greece for this reason, believing that he could unite Greece under one rule. They failed to convince King Leonidas I of Sparta to surrender to the Persians, and they grew determined to wipe out his bloodline due to its potential for interference in their plans. However, Leonidas' grandson Alexios - known to the cult as Deimos - was raised as a member of the cult, and some members of the cult would come to worship him as a demigod. Instead of advocating for the eradication of the bloodline, this faction of the Cult idolized and worshipped its members, and some traditionalist leaders such as Aspasia left the cult due to its deviation from its original views. The cult established connections in political, military, social, economic, and criminal circles, secretly pulling the strings of anceint Greece. The cult was able to manipulate the Oracles of Delphi to influence political and military leaders' decisions through false prophecies, and the cult orchestrated the Peloponnesian War between Sparta and Athens with the goal of weakening both city-states until the Cult could seize power. By 431 BC, the cult - under the leadership of people such as Elpenor, had ceased to care about restoring order to the country, and the cult's members grew chaotic and greedy and used the chaos in Greece to earn massive amounts of profit and political power.
In 431 BC, the mercenary Kassandra (Alexios' separated sister) was contacted by Elpenor to assassinate her own father, the Spartan general Nikolaos of Sparta, to prevent the Spartans from winning the war too soon (she secretly spared him and let him disappear). However, Kassandra assassinated Elpenor after he told her of his intention to have her kill her mother as well, and she later infiltrated the Cult of Kosmos and discovered their plans to assassinate the Athenian leader Pericles, to hunt down her mother, and other plots. From 431 to 422 BC, she would hunt down the leaders and members of the Cult of Kosmos, but they succeeded in assassinating Pericles and achieved many other successes.