Before the events of the first Shadow Man game, he was an unfortunate victim of a kidnapping when walking back from a pub late one night in his hometown of Dublin. Passing the University and taking a small "break", a group of students dabbling with an occult experiment kidnapped and ritually sacrificed him as a result. Jaunty would have condemned to an eternity in Deadside had it not been for Mama Nettie, who spoke to him from across the veil and convinced him to join her, to be her eyes and ears in Deadside. His reward would be that of a new body and a chance to 'live' again.
The specifics of the deal could not have been thoroughly worked out, for Jaunty appears in Deadside as a combination of a serpent with a skull for a head. His real world body became that of a disfigured dwarf. In either incarnation, Jaunty is not a pretty sight, and not much of a fighter either - hence Mama Nettie's need for the Shadow Man.
In the adventure, Jaunty is in Deadside guarding the Marrow Gates - the entrance to the world of the Dead - awaiting the Shadow Man. Jaunty is the other character that Shadow Man may seek out and converse with. His role is to reinforce and clarify the advice that Nettie gives.
In Shadow Man: 2econd Coming, Jaunty continues his role as the keeper of the Marrow Gates. When Shadow Man comes to meet him at his post, he has gone conspicuously absent. Upon returning to Liveside in New Orleans and talking to Mama Nettie, Michael Leroi or 'Mike' (Shadow Man during the day) finds Jaunty tied to a Maple tree upside down with a strange marking on his head, having been abducted by the men of Papa Morte, a rival Bokor (later revealed to be a Grigori and one of six followers of Asmodeus). Upon returning to the church, Mike and Nettie learn that the marking is affecting Jaunty violently , with snakes approaching from within him. Nettie manages to keep Jaunty from further effects for now, but instructs Mike to seek out Thomas Deacon, a private investigator who has helped out Nettie in the past. Deacon tells Mike/Shadow Man that the marking is part of a Grigori curse that can only be cured with the Grigori chalice. Mike/Shadow Man eventually finds this item and frees Jaunty of the curse. Upon returning to Deadside, Jaunty opens the Marrow Gates, allowing Shadow Man to continue his task of preventing Asmodeus's plans of Armageddon.