The Fandom Post is reporting that the entirety of the English dub of the first season of the Kyo Kara Maoh! anime has been added to Amazon Prime. Additionally, you can buy each episode for 99 cents in HD or you can buy the full season for $31.99 in HD.
The story of Kyo Kara Maoh! is described as:
Yuri Shibuya is an average baseball-loving high school student. One day, Yuri tries to save his former classmate from a group of hoodlums. Turning on him, they drag Yuri into the bathroom and push his face into the toilet. When they flush the toilet, he is transported to another world. Yuri is then taken to a castle and crowned King of the Demon World. Is he going to end up as the leader of the land, surrounded by his extraordinarily handsome lieges or will he make it back home?
Source: The Fandom Post