Designed for the largest ships in the Star Army of Yamatai's fleets. The Modular City bay was proposed as an addition by the Eighth Fleet's Shizuka Endo for the Glorious Chiharu refit. The objective was to provide a comfortable environment for recreational and life beyond service on the ship. By adding this section, the moral of the crew seemed to have been increased tenfold and provided a normality and oasis in the chaos of their work on the ship. The Modular City Bay also allows for much more compliance when it comes to long deep space missions. The city bay serves a multipurpose existence, as it can be equipped with any number of facilities depending on the mission. Most of them manned by sprites or members of the ship that are looking to earn extra wages while serving. It has also been designed to have apartments that can be added for families, refuges or any other civilian type persons.

The bay is so large that it takes up eleven decks, with an additional four around it to keep it running. Making a grand total of 15 large decks. The two on-top control weather and environmental systems. The ones on bottom provide bio-waste management, its own power sourcing, communication lines and the like.

This deck contains all forms of facilities to aid in the recreation of personnel as well as practical things, including training facilities. Gyms, swimming pools, hotels, stores, restaurants, cafes, libraries and music halls are just some examples of what is located here. Also contains the ship's gardens, a sprawling area with all forms of plant life. All centralized with a monument or fountain in the center.