The Vanguard Navy had no super cruisers prior to the commissioning of the first Leviathan, marking a major milestone for the fleet. Extra time and money was needed to make shipyards big enough to put these dreadnoughts together. However, molten metal from scrapped ships contributed to both.
The dual 24m coilguns running the length of the ship and a fourth of the height are capable of delivering gigaton-scale ordinance to the intended target at extreme velocities. Megaton-scale is the default ammunition, though the gunnery crews can easily switch to gigaton-scale projectiles.
Hangars located amidships are capable of carrying, launching, and servicing at least 1,200 fighter-sized craft. Theoretically, the hangars could be instead filled with 400 heavy bombers.