Unrailed Elevator Technology

Unrailed Elevator Technology is a technological feature that existed at some point in the Seraph of the End series. Specifically is was around in Earth's prehistoric past and was an advanced technology that existed long before humans evolved, let alone formed mechanical creations of their own. More advanced back then than anything created by humans since, Unrailed Elevator technology was involved in a seraph campaign to return them to paradise.

Details
As the name implies, elevators are involved as an upwards means of transportation and solely for Tower of Babel. The Unrailed Elevator Technology is seen to be one of the most advanced features of the quartz crystal appearing seraph civilization. Given the identification system that is a part of the Tower of Babel, status may play a role in who is able to access the elevators. From the towers mentioned to be involved in the Satellite Kingdoms it is possible that Unrailed Elevator Technology is included in outposts across different planets.

There are many small elevators that are able to be fixed to a cylinder-like interior of the Tower of Babel. Notably, such elevators are used to transport seraphs further up a tower even though they are capable of flight. They are also individually small so as to leave two seraphs and a homunculus appearing somewhat cramped within. Featureless buttons are involved with selecting a destination. Although an elevator appears to be moving physically upwards, in another case it appears to use what appears as an air based system to bring users upwards.

History
When Sika Madu ruled Earth as king he occupied the Tower of Babel which made use of Unrailed Elevator Technology. Accordingly, they were a feature of one of the tallest structures ever seen to exist in the history of the world. Such elevators were in the innermost column of the Tower of Babel. They were used by seraphs and homunculus. An announcement concerning the Babel Project mentioned the technology specifically.

Story
That Unrailed Elevator Technology was available was first learned by Yu and Mika after they have accessed memories into the past. While they heard the name and intent of the project the technology was involved in, Yu and Mika were unable to hear further details on what the deeper purpose was as they took their limited chance to infiltrate the inner section of the Tower of Babel.

Approaching an elevator, Yu and Mika decide to choose what they feel is the top floor. The elevator is used as they continue their search of Mikaela. Transported, Yu and Mika are brought before Sika Madu in the memory they are within.