For over a decade, the Space Station known as the Arc has been the center for the Nexus Fleet Headquarters. First created for a save haven for vampires, werewolves and other creatures of the night in Starfleet, the base is now use as the focal point in space due to all the portals near by to alternate realities and counter Earths.
The Arc was named after St. Jeanne D'Arc (aka St. Joan of Arc), Nick Knight's patron Saint. Nick is a former detective and former vampire now serving in Starfleet as an Admiral along with his wife Admiral Athena Zoden.
Nick Knight was the first Captain of the station followed by Captain Jadzia Dax and now it is Captain Demora.