Highlander: The Animated Series (1994)

S1E4 Melvyn the Magnificent

Ramirez brings Quentin and Clyde to a deserted mining facility to introduce them to his Immortal friend Erol, renowned for his knowledge of explosives, oil, and mining. Instead, they encounter Melvyn, Erol's disturbed and unstable human assistant, who has lost his grip on reality and believes he is also an Immortal. Exploiting their trust, he ensnares them in the mine and abducts Clyde, mistaking her for his deceased daughter. Melvyn then sets off for Mogonda, driven by a vengeful quest to take down Kortan using Erol’s explosives.