The world was not a bubble.
The passage between two worlds was not a culvert connecting bubbles, with cave-like entrances and exits.
The entrance to Black Prison above Puji Island was a Black Moon.
The Wizarding World's reflection cast upon the Black Prison World was a white rainbow— the color of a "World Gate" embodied the characteristics of its respective world, while its shape depended on the form created when different dimensions intersected.
It could roughly be understood like this: a stick from a Three-Dimensional World might appear as a circular plane in a 2D World, while the 2D World's reflection upon that three-dimensional stick might leave behind only a long, narrow mark.
The dimensional threads that made up different worlds varied to differing degrees, creating differences in the rules between worlds. That was why, even with a "gate" connecting them, communication between Black Prison and First University remained sluggish.
"Contact First University immediately! Confirm which gate has been shattered! Confirm why the entrance broke! Confirm whether there have been any casualties! Confirm the current situation at First University and Puji Island!"
"Yes!"
"Order the Star Divination Division of the General Staff to calculate whether the area covered by that White Rainbow will hinder the plan in any way. Also, have the diviners reassess the subsequent effects of the newly emerged variables."
"Yes!"
"Reduce the Guardian Formation's magical defensive support for the inner fort and main fort of Black Prison Castle. Prioritize the saved Magic Power for the Guardian Formation modules related to sensitivity, and raise the formation's sensitivity to its maximum!... If another accident occurs, I do not want the prisoners in Black Prison seeing it at the same time as us!"
"Yes!"
One order after another issued from the deepest reaches of Black Prison Castle.
The castle, once