Dai Teikoku-class supercarrier

Description
At 7,200 metres long, the Dai Teikoku-class are the largest warships in the Human Sphere.

History
The Dai Teikoku-class supercarriers stemmed from a mobile battlestation concept created during the Old Empire, Project Stardust, which sought to create a "Battle Moon" capable of independently spearheading planetary invasions and acting as a "one-ship-fleet". Following the death of Director Ono Katashi, the Imperial Navy lost interest in the concept and the design was repurposed into the Artificial Spherical Habitation Planetoid for non-military colonisation purposes, of which one was completed and another was half-finished when it was de-orbited onto Awara by Federation forces during the Empire-Federation War, killing the Emperor and wiping out much of the Old Empire's government.

During the Era of Honourable Resistance, the mobile battlestation concept would again be revisited by the Daitetsu Axis. A vastly downscaled version of the Project Stardust station was planned, but was eventually modified into a massive wing-shaped mobile battlestation, the Haken. However, the immense cost of its production, its subsequent destruction during the Coreward Frontier Campaigns, and the later collapse of the Axis meant that the Haken concept was never replicated.

Following the War of Reunification, the Imperial Navy sought to rapidly replenish its numbers. Inspired by the Haken and the Project Stardust Battle Moon, a new class of ultramassive warships was designed, an ultimate expression of the Empire's focus on battleship lines.

Dai Teikoku
Imperial Supercarrier Dai Teikoku, built as the Supermassive Carrier Initial Protoype, was the first Dai Teikoku-class supercarrier to be constructed. Built under heavy secrecy at the Onogoro Kurezora Orbital Shipyards, the existence of the Dai Teikoku was only officially unveiled years after it had been completed, simultaneously with the commissioning of is sister ship the Shin Daiteikoku.

The ship acted as a testbed for the creation of such supermassive warships, and features several design quirks that are not present in the other three ships of the class, such as a heavily reinforced internal skeleton that was later found to be unnecessarily overengineered, five fewer control towers than the subsequent ships, and three fewer hangar bays than the subsequent ships. There is also a claim that Dai Teikoku vibrates more than the other ships in the class, to the point that it can be felt by the crew, though there is little evidence to support this claim.

Dai Teikoku is currently attached to the 8th Fleet and is believed to be located around Onogoro, though has been spotted as far north as Matsutani, where it was seen flying alongside Chisei Teikoku in an extremely rare formation.

Shin Daiteikoku
Imperial Supercarrier Shin Daiteikoku, constructed as the Supermassive Carrier Production Model I is the flagship of the Imperial Navy as a whole and is also the command ship of the Capital Defence Fleet, stationed above Eienkyo.

Unlike its predecessor the Dai Teikoku, the Shin Daiteikoku was built in prefabricated sections in the Onogoro Shipyards and assembled around a skeletal structure. Built as the first production model of the supercarrier class, the Shin Daiteikoku featured several changes from its predecessor, including a stronger armament, improved power systems, an improved layout for the internal air circulation ducts, changes to the hangar layouts that created space for an additional three hangar bays, and expansion of the internal transportation monorail system, amongst other improvements.

Yamatai Teikoku
Imperial Supercarrier Yamatai Teikoku was laid down in 243 simultaneously with Chisei Teikoku as part of the Supermassive Carrier Production Model II subclass. The subclass featured further upgrades and modifications to the design compared to the Shin Daiteikoku, and unlike the earlier vessels both ships in the class are essentially identical in terms of construction.

Yamatai Teikoku is attached to the 5th Fleet, and as of 307 is located in the far east of the Empire in the Coreward Frontier.

Chisei Teikoku
Imperial Supercarrier Chisei Teikoku is currently the flagship of the 6th Fleet and is operating around the Katouku Exclusion Zone, with its home port over Matsutani. The vessel suffered heavy damage during the Empire-Hierarchy War, and underwent a repair and refitting cycle that took six years, though it is currently back in action.

Fifth vessel
A fifth Dai Teikoku-class supercarrier was laid down in 245, but was cancelled in 249 and was never completed. Records show that the completed keel was scrapped and the reactors destined for the ship were used in the Akagi-class battleships Yokoyama Reina, Kaga Kaede, and Morito Chisaki. It is believed that the fifth ship was to be named Imperial Supercarrier Shojin Teikoku.

Despite the clear evidence that the fifth Dai Teikoku-class ship was never completed, there are various urban legends that the fifth vessel was secretly completed in secret shipyards elsewhere in the Onogoro System, and is in use by the Imperial Navy or the Imperial government for various secret purposes. Suggested purposes include being an escape vessel for the Imperial Monarch, acting as a maximum-security spaceborne prison for political dissidents, a heavily-modified version armed with a planet-destroying laser, or even having been sold to a foreign power. Some individuals even claim to have seen this fifth supercarrier first hand, though little to no evidence exists to substantiate these claims.