Chrome Shelled Regios (鋼殻のレギオス, Kōkaku no Regiosu) is a Japanese light novel series by Shūsuke Amagi, with illustrations by Miyū. A short story light novel series is serialized in Dragon Magazine. A manga adaptation drawn by Miyū is serialized in the shōnen manga magazine Dragon Age Pure. A second manga adaptation drawn by Nodoka Kiyose is serialized in the shōnen manga magazine Monthly Dragon Age. A third manga adaptation drawn by Watari is serialized in Beans Ace magazine. A four-panel comic strip adaptation drawn by Masumi Futaba started serialization in Monthly Dragon Age on November 8, 2008. A science fiction light novel series titled Legend of Regios is set in the past world of Chrome Shelled Regios series, and published by Fujimi Shobo under its Style-F label. The anime adaptation started airing in January 2009 and is produced by Zexcs.
In a post-apocalyptic world overrun with mutated beasts called Filth Monsters, humanity is forced to live in large mobile cities called Regios and learn to use weapons called DITE and harness the power of Kei to defend themselves. In the Academy City of Zuellni, Layfon Alseif is hoping to start a new life and forget his past. However, his past has caught the attention of Karian Loss, the Student Council President and Nina Antalk, a Military Arts student and Captain of the 17th Platoon, who instantly recognizes his abilities and decides he's the perfect candidate to join her group. However, with a secret past that won’t leave him alone and unknown powers beyond normal, Layfon will have a hard time surviving this ordeal.