A noble, a mathematics professor and the Antiheroic protagonist of the manga, he is a genius who attempts to overthrow evil nobles and destroy the class system that has caused misery and pain to the poor everywhere.
He and his brother were orphans who were adopted by Albert Moriarty after noticing his capabilities and his ideals of overthrowing the evil nobility. At Albert's request he concocts a plan to kill the remaining members of the family and make it look like an accident. After burning the entire Manor down he adopts the name of the one he killed, of William James Moriarty, the second son of the Moriarty household and Albert's younger brother, and lives under the guise of a noble.

He adopts the title of Crime consultant as he, along with his gang, go around destroying the corrupt cast system from the shadows.