Ao No Exorcist
The story revolves around Rin Okumura, a teenager possessing abnormal strength and endurance who, along with his twin brother Yukio, was raised by Father Shiro Fujimoto, an Exorcist. One day, Rin learns that he and Yukio are the sons of Satan, the strongest of all demons.
D.Gray-man follows the adventures of 15-year-old Allen Walker, whose left arm can transform into a monstrous claw/sword and destroy Akuma (Japanese for 'demon'), evolving machines created by the Millennium Earl to help him destroy humanity. As ordered by his master, General Cross Marian, Allen becomes an Exorcist, one of the people who can destroy Akuma for the Black Order, an organization attempting to stop the Earl.