The Opposer knew exactly how Heaven and the world worked. He even knew better how the Heavens worked than the Heavens themselves, except for the highest one. The Opposer also knew how this whole situation would go down.
This lower Heaven had no clue what was currently happening in its world. The Heaven of this lower world only had strength and knowledge similar to people in the Unity Realm. The concept of a physical embodiment of the concept of lightning couldn't be understood by it.
The most probable way this would go would be that this lower Heaven was destroyed before it could even alert its parent-Heaven. At that point, this thing would ascend into the parent-middle world and then absorb that one before this Heaven could do anything. The same thing would happen until this thing reached the highest world.
What if the lowest Heaven alerted the middle Heaven immediately? In that case, the middle Heaven would first take a look at the lower Heaven's world but would find nothing because this thing was growing in power so fast that it had already reached the middle Heaven's world. This would repeat again for the higher Heaven until this thing would reach the highest world.
The Opposer realized that the highest Heaven wouldn't realize what was happening until it was already too late. If the Opposer hadn't kept a constant watch over Gravis, he also wouldn't have noticed it quickly enough.
This thing would reach the highest world and absorb all the lightning in the world. One had to know that lightning constituted a whole 50% of the total power of the highest Heaven. The highest Heaven would lose half of its strength without even having the chance to react. At that point, this thing would be half as strong as the highest Heaven in its prime, while the highest Heaven would have fallen to the same level.
The Opposer was just as strong as the highest Heaven, and this thing couldn't absorb anything from him. The Opposer would remain, and his strength would be as powerful as the strength of the highest Heaven and this thing combined. Yet, this thing didn't have allies. The highest Heaven would be its closest enemy, and it would attack immediately. At that point, the Opposer only had to wait and then kill both at the same time.
Like this, his enemy, which he had fought for over 50 billion years, would die. If the Opposer did absolutely nothing, he would be able to finally kill this last enemy of his.
That was why his emotions were riled up right now.
He had been waiting for over 50 billion years, which was many, many times longer than the second oldest person in this world had been alive for. Everything would resolve itself, and his goal would finally have been achieved.
The only thing that he had to do was sacrifice his son.
Everything shot through his mind so quickly that it could only be described in nanoseconds. His Spirit, will, and everything about him was so powerful that it was no issue for him to think this quickly. In a matter of seconds, all his problems would vanish.
Yet, he didn't want to do this!
He didn't want to sacrifice his son for this!
The Opposer was ready to do anything for power, and he had committed many things that people would call atrocities for his goal. Still, he had never even thought about sacrificing one of his children. Was he prepared to sacrifice Gravis to finally kill Heaven?
The Opposer gritted his teeth violently, and the surroundings shook involuntarily. The Opposer was shouting at himself to just do it! He had thousands of children, and he could easily make a thousand more! He could have as many children as he wanted, but he couldn't find a second opportunity to finally kill this bastard Heaven! Hell, he didn't even need to do anything. He just had to wait for a couple of seconds, and everything would happen naturally!
The Opposer clenched his teeth and fists so hard that blood was flowing out of his mouth and hands. He hadn't lost any blood since his first real fight with Heaven, over 50 billion years ago.
The Opposer sighed.
'I guess I am not strong enough,' he thought to himself. In the time it took a spark to fly off, the Opposer had made his decision.
"Old Bastard, look at what's happening in this lower world," the Opposer transmitted his thoughts to the highest Heaven in a split second.
The highest Heaven immediately checked without hesitation. If the Opposer was contacting it from his own volition, then this had to be something big. The sense of the highest Heaven immediately reached the lower world. After it saw what was happening, the skies of the highest world exploded, yet they immediately mended themselves again. It knew exactly what this meant.
"Stop!" shouted the Opposer into the highest Heaven's mind as he used his power to stop the highest Heaven from acting. He knew exactly what the highest Heaven would do. After it saw this thing, it would immediately annihilate this lower world before this thing became strong enough to become a threat. Just for safety's sake, it would probably also annihilate the parent-middle world and higher world.
Heaven's emotions had been wholly riled up for the first time in over 50 billion years, ever since it had first fought the Opposer. The whole thing about Stella in Gravis' youth, and the Opposer killing every Star God, didn't even come close to this situation! This thing wasn't only a danger. This thing was a sure-death sentence for it!
The highest Heaven transmitted infinite amounts of rage and hatred to the Opposer. All of this happening in an indescribably small amount of time.
"If I wanted you to die to this thing, I wouldn't have warned you!" the Opposer spoke to Heaven.
Heaven calmed down a little bit after that, so it asked him what he wanted.
"This thing has swallowed my son and now inhabits his body. You want to save your life, and I want my son back!" he transmitted to the highest Heaven. "You are powerful enough to influence this thing since it's still incredibly weak."
Heaven asked again what he wanted.
"I don't want my son to be swallowed by lightning. Yet, he has also chosen his path. To him, there is nothing else but lightning! So, while I restrain this thing, you make that thing spit out my son. Then, you will fuse them without any issue. My son will gain an unprecedented affinity with lightning, but he won't be a physical embodiment of the concept of lightning," the Opposer said evenly.
"You know full well that he wouldn't be able to summon and absorb lightning to gain power like this! Even if he could, as a sentient being, he would still require a strong-enough will."
The highest Heaven was not a big fan of this. Yes, Gravis wouldn't be this thing anymore, but it had never seen anything even remotely similar to this. Even the highest Heaven didn't know what Gravis would become.
"If you don't comply, I will move this thing right to my place. The only reason why we are even talking right now is that I want my son back! If I can't get him back, I might as well take the second-best option, which is your death!" the Opposer threatened.
If the highest Heaven had teeth, it would grit them. For the first time ever, in its own world, someone had something that could realistically threaten its life! This was a completely new feeling for it. Yet, the highest Heaven quickly accepted the offer.
Everything was better than dying right now.
"Don't try anything funny! If I notice anything that is not going according to plan, your death will be less than an hour from now!" The Opposer said with a voice that didn't allow for any argument.
The highest Heaven begrudgingly confirmed that it wouldn't try anything funny.
"Alright, then let's start!" the Opposer shouted.
After this, the Opposer vanished from the highest world.
All of this happened before a person could even blink, and only the very peak experts of the highest world even noticed that something had happened, though they didn't know what.