Leviathan

From Star Wars - Wiki on Neoseeker

The Leviathan is the pent-ultimate of Sith battle technology at the time of the Sith-Republic war. While not as large as some of the ships to be encountered in this game series, the Leviathan is extremely powerful and can wipe out an entire civilization on it's own in short order when ordered to bombard a planet. It is commanded by Malak, Revan's one time apprentice and betrayer, who leads the Sith in the war. The Leviathan was the pinnacle of technology at the time. Before it was commanded by Darth Malak it was commanded by Saul Karath, the mentor of Carth Onasi. It was likely that the Leviathan was the ship Malak used when he usurped the throne of Dark Lord of the Sith from Revan.