Perun manifested himself as a bull-strong middle-aged man made of cloud. Avarwizards summoned him to participate in their main attack on Thessalonica. His advance was checked through a highly unusual alliance of the ChristianGod and His emissary St. Demetrius with the Centaurs, left-over creatures of the pre-Christian Classical Greek pantheon which was overturned and driven out by Christianity - both feeling threatened by the invasion of the humanSlavs and their gods.