In a post-apocalyptic polluted earth 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.
Regios are moving cities, sheltering humanity on the barren and polluted Earth that is populated by Filth Monsters. Tired of fighting monsters and for a reason not yet revealed, Layfon left his home city to arrive at Zuellni, a city which specializes in academics and was inhabited only by students. Full of the expectation of living a normal life, he was tested on the first day of his arrival. Caught up in a fight that was rapidly getting out of hand, Layfon settled the commotion without anyone’s help. Spotted by the Student President for his martial prowess, Layfon was forced to enter the 17th platoon.
Once again, Layfon was forced back into the world of Filth Monsters and defending the city he lived in. But the secrets of this world had yet to surface…
Regios
Large Mobile cities created by humans to live after Earth atmosphere became too polluted to live. Each city is named after the Electronic Fairy that controls the Regios. Most Regios avoid Filth Monster as much as possible but with the exception of Grendan, which does the opposite as it constantly finds monsters. There are two different kinds of cities; Academy Cities & General Cities. Academy cities like Myath and Zuellni are places where students from different areas come to learn & study. General cities are the main cities where most of the population lives. Due to a treaty, only Regios of the same type are allowed to have a match with each other.
Proto-City Lance Shelled Grendan: The most powerful city in the world due to its regular encounters with Filth Monsters of all levels and was the birthplace of the Military Arts, which most other cities practice today. The Twelve Heaven’s Blades are found here under the command of the Grendan Royal Family.
Academy City Zuellni: A University City governed by its students. This is where the manga/light novel/anime takes place. Its Electronic Fairy takes the shape of a pale blue, young girl.
Academy City Gandoweria: A former city that was overrun by Pollutant Beasts not long after their victory over Zuellni two years ago. Its Electronic Fairy takes the form of an goat-like creature and is currently running amok as a Haikizoku.
Sheniebel: The city Nina Antalk grew up in, currently the only city with the Fairy Copy System which is capable of making new Electronic Fairies. Like Grendan, Sheniebel also has a royal family, which Nina Antalk is the heiress of, as seen in the manga of Chrome Shelled Regios.
Academy City Myath: An academy city like Zuellni, its electronic fairy takes the form of a red bird. In the anime, the military capabilities of this city are shown to be poor, perhaps even worse than that of Zuellni, as when attacked by a mature filth monster no resistance from the residents of the city is put up.
Transport City Yoltem: The original home city of Mayshen Torinden, Mifi Rotten and Gerlni Naruki, according to the manga. All roaming buses eventually return to Yoltem and most travelers will encounter it during their travels. Only its Electronic Fairy knows the current location of every regios.
Trade City Santoburug: The city Kalian Loss and Felli Loss grew up in.
Electronic Fairy
Special Artificial creatures that control the Regios. Created by scientists as a two-way solution of having an AI performing the many functions of a Regios while having a mind of a human for maintaining and controlling the Regios, they are the most important asset of every city. Without them, the city would die. On the other hand, the Electronic Fairy will also die if it does not have Selenium, a special ore that has many Regios fight each other for their city’s survivability. An electronic fairy whose city has been ruined turns into a Haikizoku, a being which is capable of greatly enhancing a Kei users power.
Filth Monsters
Monsters roaming the polluted earth outside the Regios. Their main food sources are the pollutants they breath into the atmosphere, humans and themselves if the former cannot be obtained. They have many forms and sizes:
Larva: The first state of the Filth Monsters. Ravenous feeders, they will eat any living thing they find. They are overwhelming in number, although easily dispatched by a skilled Kei user and expert Military Artist.
Queen: A Filth monster that lays eggs that hatch into Larva. This is the second form of Filth monsters.
Mature: A Filth Monster who has moved past its ability to procreate, the longer they live the more powerful they become. In their Mature state, Filth Monsters are able to fly. This is the third form of filth monsters.
DITE
Dites are the weapons used by Kei users. Dites are small transformable devices when unused that turn into a weapon 
which the user activates it by saying “Restoration”. Many types of weapons can transform from Dites including crushing swords, spears, rifles, staves, katanas, and many more. Some Dites are capable to switch to many different types of weapons. The color of the Dite is not random; different colors give different properties to the weapon. For example, Nina Antalk’s iron whips uses black dite, which has good density with a decreasing conductive rate. Green and white dite is used for speed-based weapons, which was suggested for Layfon Alself to use.
The Heaven’s Blade: The most powerful Dites wielded by the “Heaven’s Blade Receivers” all serving under the Royal Family of Grendan. There are twelve in existence.
Kei
Source of power for Martial Artists. Kei users are special since they have an organ within their bodies that produces this energy and Kei users can use it in many ways. There are different types of Kei each with its own qualities. In the Anime it is said that the “Heaven’s Blade Receivers” have “monstrous” Kei that makes even the strongest Kei users look weak.
External Type Kei: Used for attack. This Kei is
used in the form of a blast to affect surrounding materials.
Internal Type Kei: Used for defense and regeneration. This Kei is used to strengthen parts of the body during battle or to speed up regeneration.
Psychokinetic Kei: Users of this Kei (who are also call Nen-I users) are able to communicate telepathically as well as move objects around telekinetically. The downside of this Kei is that those who are able to use it cannot use External Type Kei or Internal Type Kei due to the fact that their psychokinesis is a fusion of internal and external kei. A person must be born with a special physical constitution to use this kei, while the other two can be utilized by anyone with training and a certain level of kei.
Layfon Wolfstein Alseif
Light novels
