UNSC Leviathan

Summary
The Leviathan is a flagship of the UNSC Navy, commanded by Admiral Micheal Stanforth. It has seen many engagements including the battle of Sigma Octanus IV, and was present during the Fall of Reach.

The Leviathan was one of the some 20 Marathon-class cruisers, sporting several MAC guns.

On page 162 in Halo: The Fall of Reach, the Leviathan is classified as a Cruiser, but on page 212, its a carrier-class (it said "They (UNSC Iroquois) docked with the Leviathan, and then the huge carrier turned and accelarated out of the system.") However this may simply be the fact that it was 'carrying' the Iroquois.

It could also be noted that with the combined tonnages of the two ships that it reached a Carrier class tonnage. It was speculated in First Strike that if two ships combined they could share power, thus creating a hybrid ship. A whole new ship, basically therefor a Carrier.

At one point in the novel Halo: The Fall of Reach it is described as "the most powerful warship ever built by human hands."