Code Geass Fanon Wiki
Class Ryujin
Ships of the Line
  • BKS Ryujin
  • BKS Mizuchi
  • BKS Moryo
  • BKS Ningyo
  • BKS Namazu
  • BKS Isonade
  • BKS Kappa
  • BKS Wani
  • BKS Ushi-Oni
Unit type Carrier Submarine
Manufacturer Republic of Japan
Operator Order of the Black Knights
  • Overall Length: 200 meters
  • Overall Beam: 16 meters
  • Overall Draught: 12 meters
  • Surfaced: 13,200 metric tons
  • Submerged: 23,800 metric tons
Equipment and Design Features
  • Multispectral Sensor System
  • 6 x Torpedo Tubes
Units Carried
  • 24 x Knightmare Frames

The Ryujin-class carrier submarine is a vessel utilized by the Order of the Black Knights in Code Geass Megiddo. The original prototype, Ryujin, is noteworthy for being the Black Knights' original mothership during the Japanese Insurrection.


Instead of the original design, the Ryujin-class of Megiddo follows after the real world Borei-class submarine.


A leftover from the Japanese Maritime Self-Defense Force (JMSDF). Something of an indirect descendant of the renowned I-400-class, the Ryujin-class submarine (named after the mythological Japanese dragon god that ruled from under the sea) was one of the largest vessels of its type to ever be constructed. An innovative design, the class featured several technologies that would be past down to next generation submarines from different nations, such as photonic masts in place of traditional perescopes, hydro jet propulsion for great mobility and quieter operation, and at the time the most advanced sonar in existence.

For weapons, these submarines are armed with six bow mounted torpedo tubes, which were capable of launching a variety of torpedo and cruise missile types. They were also originally equipped with VLS - and so initially classified as missile submarines - but these were removed and replaced with a dedicated hangar bay for knightmares and VTOLs. As a result of this retrofit, the Ryujin, in line with the I-400 before it, has since been redesignated as a carrier submarine.


While they had been quite effective in battling the Imperial Navy during the Second Pacific War, these submarines were unable to keep Imperial forces from reaching the Japanese Isles, and within a month the war was over. In order to keep these submarines from falling into Britannian hands, the Japanese underground council of industrialists and plutocrats known as the Kyoto House would secretly move them to secret harbors in the Ryukyu Islands, so that they may be preserved for future action against Britannia.

In 2017, when Kyoto House began funding and supplying weapons to the newly founded Order of the Black Knights, one of these submarines, the Ryujin herself, would be among their provisions, with Black Knights engineer Rakshata Chawla overseeing its refit with modern technology. Among the various upgrades, her original VLS were removed and replaced with a dedicated hangar bay, thereby reestablishing her as a carrier submarine. As a result, the Black Knights would utilize the Ryujin as a mobile field base throughout the final months of the Japanese Insurrection, all the way to the Black Rebellion itself.

In the aftermath of the Devastation of Japan, the remaining Ryujin-class submarines would be deployed from Ryukyu with several other vessels to transport the survivors from the ruined islands to safety. From that point on, as the Black Knights restored their forces, these submarines would once more see use in patrolling and guarding Ryukyuan territory, in case the Britannians were to return.