This character is from Katsura Hoshino's manga and anime, D. Gray-Man.
Arystar Krory III is the son of Arystar krory II, and grandson of Arystar Krory I. He is also an exorcist for the religious organization known as the Black Order. His anti-akuma weapon are his vampire-like fangs. Arystar likes the taste of akuma blood, and drinks it from them.
Arystar was kept from knowing he was an exorcist from his former assistant and lover, Eliade. eliade allowed Krory to bite her neck, and she made him think he was a vampire. The village hated him for this, because he had drained the villagers of their blood. Eliade was found out to be an akuma when Allen Walker and lavi showed up at his castle. Arystar was then told he was an exorcist and he killed Eliade, who had transformed into her akuma form.
Arystar was taken to the Black Order where he recieved his exorcist uniform and helps the other against the war.