Nichol the Electrician serves as an antagonist driven by a personal vendetta against the central protagonist, Mad Bull. He leverages his connections to New York City's criminal underworld to pursue this goal. His primary function involves designing and constructing unconventional, often deadly devices for criminal operations and assassinations. Notable creations include firearms integrated into hard hats and harness-mounted shotguns affixed to cats, emphasizing surprise attacks through unusual weaponry.

A key tactic exploits Mad Bull's documented soft spot for animals. Nichol deliberately weaponizes animals, particularly cats, fitting them with explosive harnesses or inducing frenzied attacks against his target. This method crosses ethical lines to provoke a fierce response.

Physically, Nichol is characterized by diabetes and a compulsive canned coffee addiction. This habit produces a distinct, unpleasant odor frequently described as a mixture of sugar and urine.

The character's name appears with variations across sources, primarily romanized as 'Nichol' or 'Nickel', and sometimes 'Nickels' in the manga. This naming is often suggested as a potential reference to actor Jack Nicholson, whom the character's appearance reportedly resembles. In the English adaptation of the anime, his occupational title was altered to "Nickels the Mechanic". His depiction remains consistent as an inventive underworld figure defined by his grudge and tactics that cross ethical boundaries.