"Wer mit Ungeheuern kämpft,
mag zusehn, dass er nicht dabei zum Ungeheuer wird.
Und wenn du lange in einen Abgrund blickst,
blickt der Abgrund auch in dich hinein"
- I-401's motto seen on the port side of her sail
's Super Graviton Cannon in primed position
Having extensive modifications from the Fog's standard I-400 class attack submarine, I-401 housed the most powerful processor core of any Fog submarine, capable of managing weaponry usually only possible for flagships. She was the first vessel in the Fleet of Fog to create a Mental Model, and was one of the first Fog vessels to appear.
I-401, along with her Mental Model Iona and her Human crew would gain fame and infamy under several names, including "The Blue Steel", "Battleship Killer", and "Traitor".
Serving as Humanity's last hope against the omnipresent Fleet of Fog, she would be instrumental in the survival of the Human species itself. Surmounting any odds, in battle or in diplomacy, mostly thanks to the genius and cunning of both her Mental Model and her captain, Gunzou Chihaya.
She would sink the Fog battleships Hyuuga
, the cruisers Nagara
, and Nachi
, the submarines I-501 and Milchkuh
, and she would be critical in the sinking of the battleships Haruna
Displacement: 5,223 long tons surfaced, 6,560 submerged
Length: 122 m (400 ft)
Beam: 12 m (39.3 ft)
Draft: 10.2 m (33.5 ft)
Propulsion: Two graviton thrusters generating an unknown amount of thrust
Speed: 60 kts surfaced, in excess of 100 kts submerged
Armament: 8x Torpedo tubes, 11x Photon cannons, 18x Missile launchers, Super-Graviton Cannon, 3x Seiran Bomber Drones
Protection: Klein Field emitter, Wave-Force Armor
Mental Model: Iona
"This is really quite bad." - Unknown sailor on board the battleship Ustoppelig
, moments before magazine detonation