Nite Owl is a vigilante in the Watchmen universe who uses various skills to fight crime without any superpowers. The original was Hollis Mason, a police officer who dreamed of adventure and became a crimefighter to satisfy that need, utilizing his hand-to-hand combat skills to take out criminals. He joined the Minutemen, and stayed with them until their split, when he then entered a happy retirement of fixing cars. He released his tell-all book about the Minutemen, Under the Hood, a few years into it.
Hollis trained his successor, Dan Dreiberg, after releasing his book. Dan took advantage of his massive inheritance and engineering know-how to build various gadgets and machines to assist him alongside his partner Rorschach on top of their combat skills. He felt lost when he was forced to retire, but found purpose again through his lover, his former teammate in the Crimebusters, Laurie Juspeczyk.
Hollis and Dan are analogues for the Dan Garrett and Ted Kord incarnations of the Blue Beetle, respectively.
Nite Owl was created by Alan Moore and Dave Gibbons, both Mason and Dreiberg first appearing in Watchmen #1 (1986).
Watchmen Universe
Original
Multiverse
The New 52
Earth 4
Based on Mason
Earth 4
Based on Dreiberg
Reality Undetermined
Woofmen
Pre-Crisis
Earth-Four
Basis for Hollis Mason
Earth-Four
Basis for Dan Dreiberg
Earth-S
Mary Marvel villain
Other Media
Watchmen Universe
Other
DCAU
The Zeta Project
Comics