The Anti-Wave Shell (対波動シェル, taihadou sheru?), commonly known as the Shell, is the name given to the enormous clockwork-like dome that covers the entirety of Ra Ciela's NS magnetic pole, and it is a metal convection field or dynamo created by the Tenmon a few decades prior to the events of Ciel nosurge: Ushinawareta Hoshi e Sasagu Uta, which serves to shield the areas it covers from the radiation and rising temperatures that have become the normal fixture in Ra Ciela due to its sun, Bezel having become a red giant. This has caused its solar winds and solar flares to overpower the planet's natural magnetic field, rendering it uninhabitable excepting for the areas protected by the Shell.
As their creators, the Tenmon are also tasked with the Shell's management and maintenance, and the Shell itself covers an area that is 70% land and 30% sea, accounting for part of the small water bodies that still exist in Ra Ciela and for the only piece of land where life can still prosper: all other areas aside of where the Empire is currently located are no more than a wasteland that features the ruins of destroyed cities, dead plants and dried water bodies as a consequence of Bezel having become a red giant.
While trees and other large kinds of vegetation can be found all over in the areas near the center of the field covered by the Shell, the further one goes away from it, the smaller the plants become, to the point that only weeds can grow next to the Shell's area limits.
The Shell serves as the lifeline to the inhabitants of the only nation that remains in Ra Ciela, the Empire, in particular for the residents of Old Capital Manjusara, but it has also become a hazard for them in recent times: given that the Shell has withstood a constant onslaught of radiation and plasma that Bezel sends off in the form of Wave Bursts for many years, it started breaking down five years before the start of Ciel nosurge, so it has become a recurrent news bit for pieces of the Shell to break and fall off it as debris, crushing the parts of the city they were supposed to protect and causing many deaths in the tragedies knwon as Shell Collapses. And to make things worse, once a Shell Collapse has occurred, the area where it took place will be exposed again to the radiation and high temperatures, meaning that said area will be utterly destroyed when another Burst comes. It is due to this that the Imperial Government issues an evacuation order to all the survivors residing in the area where a Shell Collapse occured and declares that area as an Exclusion Zone.