Professor Moriarty stands as the primary antagonist in the narrative. Departing from his literary origins where he manipulated a vast criminal network from the shadows, this version actively participates in crimes and encounters the protagonist and allies directly. He operates without a large support system, typically relying on only two consistent henchmen.

He is an intellectual and master inventor whose technological creations fuel the setting's prominent steampunk elements. He designed and employs a distinctive personal vehicle, a steam-powered hybrid resembling a cross between a tractor and a tank rather than a standard automobile. His criminal schemes frequently involve complex, seemingly illogical plans requiring the connection of disparate, unusual events. This very complexity becomes a key trail his adversary follows to deduce and unravel his activities.

His plans target valuable items, such as the intricate theft of a famous blue ruby. In a later scheme, he progressed to stealing a top-secret military submarine from the Navy. The motives behind acquiring such technology often form a central mystery pursued by the protagonist. While primarily driven by personal gain, he occasionally accepts mercenary work from other criminals, targeting objects outside his usual interests.

Physically, he resembles an anthropomorphic gray wolf. His two main henchmen are Smiley, a tall, lanky individual with limited intellect and a Cockney accent, and Todd (sometimes inconsistently called George), a small, squat figure who frequently voices criticism. Both provide comic relief and were formerly members of a pirate crew before joining his operations, often finding themselves in comedic situations during botched criminal attempts.

His relationship with Mrs. Hudson differs significantly from traditional portrayals. She is a young widow, and he harbors romantic feelings for her, a sentiment shared among other male characters. This dynamic occasionally influences story interactions.