The only way Celestials grow stronger is to imbibe more domains. They are unlike Origin gods and Demon kings who sacrifice concepts and Celestial Godhood respectively to grow their Authority. But the tree father won't remain in his stagnant situation for long.
So Aeternus has reached the limit of the path for a demon king. He can't initiate his evolution yet because his evolution is not normal. He has to contend with primordial chaos to become a demon god. So he is waiting to fully comprehend the law of Chaos before he attempts the fusion with his mark of sin.
The Godhoods he is acquiring are for the tree father to grow stronger since he doesn't need them anymore. He much prefers to empower himself with soul force.
His Authority was changed due to the shard of power and he has become able to utilize soul force in ways that the other clones can't. So he has been using Soul Force for a lot of things. The current weapon that this avatar is using is made out of soul force. The black armor on his body was also made out of soul force. Even the avatar was made out of soul force.
Soul force can also work together with his Authority seamlessly to create stronger attacks. Godhood can't empower him anymore but Soul Force can. His soul can produce soul force on its own since he is a fragment of an Origin god's soul. But the soul force that he produces on his own is not as powerful as the soul force that Legion-1 produces. And thanks to the soul sphere, Legion-1 can give him some soul force.
So Aeternus can use both his Authority and the power of Legion-1's very powerful soul. That's how this level 5 clone is strong enough to take on the entire pantheon. This means that even a demon king with a level 10 Authority won't be a match for his main body.
So one might wonder why he is here working together with two other demon kings to subjugate a divine plane. After all, he can take on the entire Celestial Pantheon on his own with just a single avatar. If he can subjugate the plane on his own, why is he working with two demon kings and why is he hiding his strength too?
Aeternus waited patiently within the cloud to pretend that he was still fighting while the others were fighting outside. The succubus queen used her whip to fight the Celestial of Lightning and the snake demon king used his curved blades to fight the Celestial of Wind.
Those two Celestials are the fastest among the 6 Celestials still alive. The Celestial of Light is the fastest Celestial but she was downed from Aeternus's first attack. She wasn't fast enough to dodge the black beam. These two are the next fastest but their speed won't be able to help them evade their fate.
The Celestial of Lightning is a giant purple snake with wings. Its entire body of about 70 meters long is made of lightning so it is very fast. It zaps about with lightning speed and it produces attacks using lightning bolts. Each of its attacks is accompanied by a flash and a boom of world shaking thunder.
The succubus queen can't keep up with the speed of the Celestial of Lightning but she doesn't need to. Her red whip is fast enough to hinder the elusive Celestial. She wields the whip so well it is like a sentient snake in her hand that is capable of tracking and constricting whatever it gets a hold of with considerable strength.
The whip is thin and long but it is very strong and durable. It is also very sharp so it can slice through very tough metal and it can decimate flesh. It strikes with the force of a club while simultaneously cutting like a blade. The area where it hits is pulverized.
The whip will first slice open the spot it hits with unparalleled sharpness. Then the head of the whip gets into the wound and ejects explosion force that mimics blunt trauma. This makes the wound expand from the inside out and explode. The whip can also extend for a long distance and split apart at the edge. When coupled with her proficient wielding, it becomes a very deadly weapon.
The Celestial of Lightning fell into a disadvantage quickly because of the whip. Its powerful attacks can level a mountain and tuurn it into a crater but Its attacks couldn't hit the succubus. Her body always turns into red smoke when she's hit either by lightning bolts or physical attacks. Succubi are very good with illusions so a demon king succubus must have top-notch illusion-based sin abilities. The Celestial of Lightning can't tell where she is so it is hitting her illusions.
The Celestial of Lightning couldn't make effective attacks because of the illusions and the compromise of its senses also affected its defense. It couldn't dodge the whip attack because it saw hundreds of whips instead of one. It doesn't know which one is the real one so it has to pay with its flesh as its price for being fooled.
The whips gouged out chunks of its body and soul. It felt pain throughout its entire existence. The pain is so great that it could cry. Its injuries accumulated until it became desperate. So it activated an area of attack ability.
The purple snake of lightning formed a domain of lightning around it. The domain formed a sphere of lightning around it that smashed and destroyed everything within the domain to ashes. It also allowed it to acquire accurate information about everything within the domain.
A domain grants higher control of an area by creating direct access between that area and the soul. The Celestial of Lightning used this access to bypass the illusions. It was able to find the succubus this way. It locked onto the demon king of lust and gave chase immediately. One of them must die and it will either be through destruction by lightning or by being bludgeoned to death by a whip.