Blue Exorcist is a Japanese manga series written and illustrated by Kazue Kato. It was adapted into an anime by A-1 pictures.
The supernatural action story follows main characters and twin brothers Rin Okumura (older) and Yukio Okumura (younger) as they protect Assiah (the human realm) from Gehenna (the demon realm). Interestingly, they were raised by an exorcist Shiro Fujimoto, but are actually sons of Satan. Even more surprising, Yukio is already a seasoned exorcist and teacher at the exorcist cram school True Cross Academy while Rin is just beginning to learn the ways of exorcism.
Other exorcists include Ryuji Suguro nicknamed “Bon,” a fellow student who’s sworn he will defeat Satan and rebuild the Cursed Temple; Shiemi Moriyama, a kind girl with a love for gardening and who is Rin’s love interest; tsundere Izumo Kamiki who is a talented student; kind and strategic Konekomaru Miwa who plans to achieve the Meister in Aria; and carefree Renzo Shima, nicknamed “Erotic Demon” due to his infatuation with women, who also plans to achieve the Meister in Aria and whose loyalty to the True Cross Order is sometimes rightfully doubted.