Rin Okumura Ao no Exorcist Blue Exorcist
"If you continued liked this.. one day you will always be alone.."
Rin's childhood was spent under the care of Fujimoto, the strongest exorcist, who claims to be Rin's loving father. When Rin was young, he was naturally dangerous whenever other people or kids mocks and judge him. They would constantly call Rin a demon, and they try to get away from him. Because them, Rin throws tantrums and wrecks almost anything that is in his sight. The more he acts crazy the more the people are afraid of him. And because Rin grew up knowing that people would always judge and hate him, he accepted that he would never be able to fit in. His childhood dream is to become someone like his father, Fujimoto, and to become a respected person popular with the girls.
"If you keep on struggling, eventually.. before you even notice it, you will become such a person."
Rin's powers was sealed by Mephisto Pheles in the demon slaying blade called Koumaken. However, the seal broke days after Rin graduated from middle school. The powers that he inherited from satan was fully released when the koumaken's seal weakened, while another demon tries to hurt him. When a demon was about to deliver Rin to satan, Rin was saved by his adopted father and guardian, Fujimoto. As they hurriedly reached the monastery, Fujimoto requested Rin to leave the place and must hide for a while. Confused, Rin disagrees with Fujimoto and tells him that none of the stuff that he learns about himself makes sense. As Rin gets frustrated he thinks that his guardian, Fujimoto, just wanted to get rid of him instead of protecting him.
"Don't you ever act like you are my father again!!"
As Rin spouted hurtful words towards Fujimoto, Fujimoto became an open target to satan and was then possessed. Because the existence of satan in the Assiah cannot exist, Rin becomes the target of satan to fullfill his goal to take over Assiah, the dimension where demons does not exist. Rin's existence is the answer to satan's goal, because Rin can exist in both dimensions: Assiah, where humans exist without demons, and Gehenna, the dimension of demons, even though Rin is a demon himself. At the moment where Rin was nearly taken by satan, satan was stopped by his Fujimoto who is taking over his body back. In the process, Fujimoto died and Rin was able to close the gate of Gehenna, by releasing his power and using the Koumaken. However, as Rin uses the Koumaken, his demon nature where released, and he could never go back as a human ever again.
To survive, Rin keeps his father's words to himself. He requested to Mephisto Pheles that instead of being killed, he wants to join them and become an exorcist. Surprised, Mephisto, a friend of Fujimoto, agrees to Rin and finds his decision interesting. As he becomes a student in True Cross Academy, Rin must study exorcism in cram school and must hide his blue flames to other students. He also learns that his twin younger brother, Yukio is already an exorcist and also a professor and a well known genius.