He first appeared in "Portrait of a Mutant", the Scottish leader of the rebels in the mutant war and an ally of a young Johnny Alpha. After the war, he became a Search Destroy Agent and first appeared in the present day in "Outlaw"; he appeared infrequently after this, and after the death of Johnny's partner Wulf Sternhammer, McNulty would become Johnny's new partner in many strips. Initially, he had a running gag of his Scottish dialect being incomprehensible to the English characters but this would be dialed down – his hooligan ways would continue to be a source of humour though.