Inspired by ancient Greece, Theros is a plane ruled by a vast pantheon of gods who rule from the starlight realm of Nyx. Divided into three realms, Theros has a physical underworld that exists beneath the surface of the world, and a celestial one that exists within the night sky and holds the gods and their creations. The pocket plane of Nyx is absolutely unique in the multiverse, in that the belief and devotion of mortals on the plane effect the fabric of it and the gods it houses. Enough communal belief from the mortal races changes the fabric of reality, and can create or destroy gods, making it as if they had always existed, or never existed at all. The depths of the underworld, on the other hand, is rather immutable: home to all the lost souls of the world, good or bad, and separated from the world of the living by The Rivers that Ring the World. On the sun-lit surface of Theros, humanity lives within numerous large city-states known as Poleis, divided and content after their triumph over the old Archon rulers of the plane. Within the wilds of Theros there are civilizations of centaurs and satyrs, hulking hydras, sphinxes, dragons, sirens, manticores, cyclopes, giants, and pegasi. Off its massive coast are cities of merfolk known as Tritons, sirens, harpies, and enormous kraken that patrol the deeps. The world is home to as many heroes as it is monsters, and all great deeds are done in the name of one god or another. The only exception are the Leonin of the Therosian planes, who answer to no god after throwing off the Achon rulers of old. Theros is also the home plane of the planeswalker Gideon Jura, who was born as Kytheon Iora of Akros, and the planeswalker Niko Aris from Meletis.