Originally designed by Ensign Kirk Ambrose as a fighter\escort for the original Leviathan. Ensign Ambrose's idea was to create a vessel the size of a Danube class runabout, but as powerful and manoeuvrable as a Defiant class starship. Although his vision was ambitious, Captain Devore allowed him to proceed.

The vessel's design was too large to be accommodated in the Leviathan's shuttlebay, so instead the vessel was built in the main cargo bay, meaning that the Hellcat had to be 'dropped' from the underside of the Leviathan.

Taking one of the Leviathan's two Danube runabouts as a base, with the assistance of the crew and a large amount of salvaged parts, the Hellcat was built in just over two weeks.

The Hellcat has served the crew well, acting as a 'lifeboat' to over a hundred of them when the Leviathan was destroyed at Limerus IX.

Over the years, the Hellcat has been modified and added to, turning from a vessel primarily designed to be a fighter into a shuttle with the 'teeth' to defend itself. These include setting up a combined science lab\medical bay.

The most significant modifications came after the Leviathan-A returned from the Andromeda-Cirrus galaxy. The Hellcat had suffered heavy damage whilst attempting to escape a black hole. Once returned to a starbase, the Hellcat had a complete overhaul, including the replacement of the Klingon disruptors with phaser cannons, the addition of three more torpedo launchers, dual layered shields and the installation of a prototype micro slipstream drive.