Plane Prison and the Yulan Plane were two sides of the same coin. Every material plane had such a place, and its existence could no longer be traced; at the very least, it had existed for countless hundreds of millions of years.
Those imprisoned within were 'fiends' whom each successive plane overseer deemed necessary to lock away. Usually, though, the plane overseers simply acted tyrannically according to their own preferences. Even if only a few were imprisoned every ten thousand years, the prison would already be packed to capacity.
However, because Yulan had Beirut, its plane overseer, Huodan, was nothing more than a clay idol with no real use. Beirut was instead the one who frequently imprisoned people. Five thousand years ago, Delin had been locked up by Beirut simply because Beirut disliked his innate divine ability.
Those imprisoned in Plane Prison were, at minimum, Saint-level beings. Saint-level beings could already survive without food or water and never die, which made Saint-level prisoners nothing more than common fodder within Plane Prison...
"Delin might have already been killed by Grizzly Bear."
Pomonter, Muba, and the Great Wizard had been forced to band together due to the sudden pressure of a Middle God. In the past, the four Lesser Gods, including Delin, had occupied all the surrounding territory.
Originally, aside from Delin, Pomonter was the strongest, and he also had the worst temper. Under normal circumstances, he would have eventually consolidated the nearby forces, then led the Great Wizard and his other Saint-level underlings through the increasingly weakened node into the Yulan Plane to stir up chaos.
But Delin had escaped ahead of time, and the Middle God who had suddenly arrived after sensing the disturbance had clearly thrown his entire plan into disarray.
As a result, he had no choice