Gary is first seen in The Big City where a time capsule of Shirley Dixon is being dug up after a hundred years. Gary claims to have been there in 1906 when the capsule was originally buried. Gary and his posse, consisting of Samuel Larson and Marty, kill the Deputy Mayor in order to get Dixon's diary (the voice of a mute). With the left hand of a innocent murderer already in their possession, the last piece they need to leave the Ghost River Triangle is the locket of Stanley Gatewood's wife (a loveless heart). Wynonna Earp and Xavier Dolls arrive at Crown Surplus just as Gary's group starts taking hostages. They release three of the hostage, but keep Champ Hardy and Shorty, in return for Wynonna's help in opening the safe. Marty gets frustrated trying to open the safe without the combination and ends up temporarily killing Gary. Since he wasn't killed with Peacemaker, Gary should have been able to resurrect eventually. Depending on how long it took him to come back, it's likely Wynonna went back to Crown Surplus and sent Gary back to hell after killing Sam and Marty.
Despite working together for many years, the three of them aren't particularly close to each other. Sam doesn't seem upset when Marty temporarily kills Gary and later Sam shoots Marty when they fight over Champ's body.
Dolls suspects that they channel the powers of a hellhound
- Super strength
- Increased speed
- Finely tuned sense of smell
- Marty says they waited 15 years for Gary to resurrect. This means he was probably sent to hell by Ward Earp shortly before his death and resurrected when Wynonna became heir.