Louis Devereaux (or 'Dev' as his friends call him) is a special agent for the FBI, handling cases in New York City.  He's mainly a night person, preferring to sleep during the day and getting up shortly before dusk.  He's known to frequent a bar/nightclub called Club Redrum, since he's good friends with the owner/barkeep, Cliff Lee.  He's also friends with another frequent, Anders Larson, but Larson wasn't initially aware of Dev's job.

Dev's main hobby, however, was searching for the assassin Enoch Anderson.  Years earlier, Dev had been partners with Bill Redman, and both were assigned the case of Anderson, a contract killer.  When they apparently had him cornered in a warehouse, Anderson killed Redman and escaped, leaving Dev upset and vengeful.  For ten years he pursued Anderson while working other cases, but was eventually shunted to NYC as Anderson's trail ran dry.

Then, Anderson was hired by someone in NYC to do away with a homeless man named Raymond Gamin.  Following two unsuccessful attempts by Anderson, Dev got his case back and went after Anderson, and with the help of Raymond (who was revealed to be a fey named Anyx) was able to capture him and put him in prison.

Dev later heard the whole story about gargoyles and the Third Race, then Anyx's story, and quietly absorbed the information.  It doesn't change his outlook all that much, but he's more inclined to believe the gargoyles' side of stories now.