Kappa Nebula is a nebula located somewhere in the galaxy's Alpha Quadrant.
History and specifics[]
According to a Starfleet Academy simulator scenario, a Constitution-class intercepted another ship of its class; right after the destruction, it was revealed that the ship was actually a refitted Venturi ship, used to attack Tholian starships, causing a crisis between the Tholian Assembly and the Federation. (ST video game: Starfleet Academy Starship Bridge Simulator)