Moriarty is a scheming individual who had planned to destroy the world by any means necessary, even through the use of betraying the protagonist after becoming close to them. His desire to defeat Holmes also motivated many of his actions, including the aforementioned plan, even as a servant he loathes his nemesis to no end.

having the body of a 55 years old man. His white hair is slicked back with a single strand hanging over his right eye a well elgant mustache as well as a suit fitting of a gentleman of the english aristocracy, often wearing a white long sleeve white shirt, black vest with gold ornaments, a tailored suit and leather gloves, polished shoes, his sword cane and a hidden pistol under his sleeve with a retractable mechanism, he stood with his arms behind his back studying an algorithm on a chalkboard he had been using, he enjoyed himself being a mentor of sorts to the younge servants of Chaldea.

"Now let us discuss the trajectory of the-..oh. young master are you interested in joining us?." Moriarty noticed the master standing on the door frame.

"You can take a seat of course, the more the merrier.." Moriarty's soft refined English accent evident as he continued, however there was that glint in his eye, a plan already forming inside the Napoleon of crime..