William Moriarty

Because of his unique gift and his desire to protect others, William feels alone, despite the love and support of his family and friends. Because of this distance between him and his allies, they cannot convince William of his determination to pay with his life. However, in Sherlock Holmes, he finds an equal and the only one who truly understands him. Although William has always been solely focused on executing his plan, he realized he wanted to befriend Sherlock and even considered giving up everything to be with him. Ultimately, it is Sherlock who saves him and shows him that death is not redemption. After this, William struggles to find his own path and understand how to atone for his guilt. During this period, he is quite reserved and sentimental, even crying several times. However, William ultimately realizes that there is no single right answer and that constant hesitation is a part of life. He vows to Sherlock to continue living and fighting together.

Having come to this conclusion, William becomes much more determined and cheerful, and can even fight again. Three years later, Paterson and Jack note that he smiles more often again and has become more like his younger self. William is determined to atone for his actions for the rest of his life. He has a habit of suddenly falling asleep due to overthinking. This happens even while eating, in the bath, or in the middle of a conversation. The action takes place in the nineteenth century, during the Victorian era, when only the children of the nobility and wealthy attended universities.

William was kind and polite, yet also highly intelligent and incredibly erudite. Even at a young age, he read and wrote well, and his intelligence and quick wit helped others. It is said that he often entered the library without permission, where he learned much along with his brother. His knowledge impressed many adults, and children loved him. He preached to them that corrupt nobles deserved punishment. As a child, he was a mathematical prodigy and excelled in his studies, even winning a King's Scholarship along with his brothers and becoming a university professor at an incredibly young age. As an adult, he developed into an elegant gentleman, an impeccable aristocrat from head to toe. He is charismatic and eloquent, easily winning the respect of others. Thanks to his intellect, he easily recognizes lies, understands others, and is adept at planning crimes. William is adept at organizing and executing flawless operations, leaving no trace, and manipulating others into doing his bidding. Despite his brutal actions, William is an incredibly kind, compassionate, and gentle person. He is friendly with everyone around him and cannot ignore those in need—he is willing to help anyone, even unsolicited. From a young age, he was determined to make the world a better place, striving for justice and equality. Knowing the cost, William was willing to sacrifice himself to carry out this plan. William is deeply attached to his family and allies. He never showed them the tension he was under, with the exception of Albert, and always maintained a calm and confident demeanor. Although his allies were also willing to give their lives for this plan, William decided from the start that he alone would perish.

During "The Final Problem," the crimes and violence he committed begin to take their toll on him. He appears depressed and loses his former expressiveness. William cannot forgive himself for all the murders and bloodshed.

He is a brilliant mathematician who, disguised as an aristocrat, wages a secret war against the corrupt British nobility, taking on the role of "crime consultant." William is described as a handsome young man with scarlet, "expressive" eyes. He has pale skin and a slim build, with medium-length, light-colored, curly hair with a long side fringe and a longer side fringe. He is said to look better when he smiles.

He typically dresses in classic suits, appropriate to the Victorian era and his social standing. His appearance is neat and tidy. He often carries a cane, which is actually a disguised blade, and wears a top hat. During certain "missions," he also wears a black hooded cloak over his regular clothes, covering his face. He always wears a formal brown three-piece suit with a red tie. A cool-headed genius who rarely loses his temper, William is already a professor of mathematics at Durham University at the age of 24. A true genius, William has demonstrated his extraordinary intellectual abilities since childhood. He possesses a charisma that draws people to him. He also feels compassion for others and has a heightened sense of justice.

The qualities he developed in childhood help him gather people who share his views as he grows up. He has an extremely negative view of the current social system, which encourages class inequality. In pursuit of his goals, he displays cruelty toward those at the top of this system and compassion for those at the very bottom.