All the demons till the high-rank level need sin energy. A low concentration of sin energy will prevent them from growing. The absence of sin energy will cause them to start to die. The sin energy in their body will escape forcefully into the surroundings and they will weaken. They can prolong their lives by eating each other but they are doomed unless sin energy is made available again.
The detachment of the plane will also cause it to be disconnected from the demon sire so there won't be production of new demon fledglings. Demon nobles and the demon dukes will be alright in the absence of sin energy.
But the plane needs the energy. It won't be able to run without a constant supply of energy. A prolonged lack of energy will cause it to start to break down. Any demon king that detaches his or her plane will need to reconnect it soon or risk losing the entire plane and becoming a plane-less demon king.
These things haven't happened yet but he can see the beginnings of them. They will surely happen if nothing changes about his situation. Fortunately, Aeternus doesn't need to do that. He has always had an infinite supply of energy so he is not helpless in that aspect.
He chuckled deprecatively, "I am a fugitive demon king. I haven't fallen so low as to become a plane-less demon king."
He switched the supply of energy from the energy sea to his own soul. Infinite chaos energy flowed directly to the core of the plane. The shiny core was flickering earlier. It shut down now that this new energy entered it. The light it was giving off died down completely and the plane was plunged into darkness.
The core didn't die. It just wasn't designed to be used with chaos energy. It can use it to sustain itself without burning up because it is connected to Aeternus's soul. But that's all it can do with chaos energy. It can't produce light at all.
Aeternus shrugged and said, "It's alright. Demons don't need light anyway."
The plane will survive and that's all that matters. Every demon can see in the dark. High-rank demons and above don't even need eyes anymore once they get their divine sense. The only advantage of eyes is that it has a farther range.
He can make his chaos energy flood the plane to replace sin energy but it will be counterproductive. Only his direct subordinates with his chaos spark within them can use his chaos energy. The rest will be destroyed.
So either way, he will lose most of the demons in his plane apart from his direct subordinates. They will die because of the lack of sin energy. He is already losing access to the other planes that his subordinates are the demon lords of. His subordinates left those planes for their safety. The loss of those planes and the demons in his plane means that he will lose his entire army. It can't be helped. It is the price for safety.
He sat on his throne as he oversaw all the changes to the plane. His eyes shone brightly like two golden stars. He inspected both the internal situation of the plane and its exterior. He relaxed when he didn't notice anything out of place.
His plane detached from the abyss with a large disturbance. There was no one there to see it. His avatar is doing a good job of distracting his enemies so they are distracted.
"I will probably lose that avatar at the end of the day."
That is what he thought as he became a runaway demon king. His plane began to wander around the energy sea. It sank further below into its depths where it won't be found. No demon God will be able to find him easily now. He made sure everything is in order before he closed his eyes. The two golden stars of his eyes shut down as the 1696th plane of the abyss became a wandering plane.
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Somewhere Far Far Away.
Somewhere deep and far below the energy sea of the abyss is a very large ocean. It is where all the energy seas of every abyss in the void universe come from. The water of this large ocean is purple like that of the energy sea but it is very thick. It is thick and highly viscous like blood or tar.
This water travels from the ocean and rises in what can be considered an upward direction into the abyss. This direction applies to entities that can only see the world in 3 dimensions. To those who can see in more dimensions, the water of this ocean collapses into the abyss from the direction of lower space-time. It doesn't rise into the abyss.
If you want to trace the source of the bloodlike liquid that formed the ocean, you will need to delve further below this ocean. Of course, any being that can do something like that needs to be a world ender at least. Only such a being can withstand the pressure of the ocean depths and the pervasive nature of this bloodlike liquid without being corrupted. A world god cannot come close to these depths or risk complete death.
But even a world-ender will have to cut the trip short. This is because the bloodlike liquid changes the further below you go. Its purple color darkens. It becomes violet. Then it becomes black. It is a deep black that looks very similar to the energy that Aeternus uses.
The bloodlike liquid has become almost solid by now. The pressure it is emitting will crush any being. A world-ender will feel like an ant encased in a diamond. The solid black energy has also become so corrosive that it will corrode anything and anyone with just a memory of it. Anyone who so much as thinks about it or sees an image of it will be corroded both in body and mind.