"Tail Gunner" (real name unknown) is a homeless man and a member of the Route 666 Community in the tunnels under New York City. He is small and thin with a long face and an extremely long beard shaped into two points near his belly button. He has a gravelly voice and a grimy appearance. He was a Vietnam veteran. His reasons for going underground are not known.
In Reliquary, Tail Gunner acted as a runner for Route 666's leader, Mephisto, making trips to the surface to buy food, collect recyclables, and so forth. On one of his trips to the surface, Tail Gunner procured a copy of the New York Post and brought it to Mephisto. Mephisto read an article in the Post about the murder of socialite Pamela Wisher. He asked Tail Gunner to track down the article's author, Bill Smithback, in order to tell Smithback about similar murders that had been occurring in the underground community.
Smithback met Tail Gunner in a men's room at Penn Station and followed him into the tunnels. Smithback refused to descend into the deeper levels where Route 666 was located so Mephisto spoke to him from below through a grate. After their conversation, Tail Gunner escorted Smithback back to the surface.
Later, Special Agent Pendergast and Lieutenant Vincent D'Agosta visited Route 666 while investigating the New York Underground Murders. Tail Gunner acted as Mephisto's lieutenant and brought the two men some "track rabbit" (roasted rat) to eat.
When the homeless in the vicinity of Central Park were rousted from their home by police during the final Take Back Our City march, Smithback thought he saw Tail Gunner climb out of a manhole followed by other homeless. His whereabouts after this time are not known, but presumably he returned to the underground.