Titan

The Titan was a type of fleet craft that was used by the Colonial Navy during the First Colony War. They were considered to be a rare sight, due to their development only being completed once the uprising against the Earth Empire was well underway.

League craft database
"'The origins of the Titan are unknown. It is a recent addition to the Navy's fleet and is regarded by Empire commanders as the weapon which will ultimately smash the League of Free Worlds uprising. Analysis of the Titan's alleged capabilities suggest that it my be capable of destroying entire worlds, although such speculation is yet to be confirmed'."