There is a logical reason why the god of fate should be killed apart from the unforgivable hatred between them. Killing the god of fate will grant Legion total control of the Zargoth plane. So it is highly beneficial to see the current Celestial dead.
Aeternus's determination to kill the god of fate sealed his fate. Even that single future disappeared after Aeternus spoke. The future vision of the god of fate showed nothing but darkness after Aeternus made up his mind to do the deed. The god of fate has gone from having numerous futures to having none at all.
The god of fate laid down flat on the ground and sighed. "Just get it over with." He murmured.
Aeternus was perplexed. He asked. "Aren't you going to run or defend yourself? Stand up and fight."
"It's no use. I'm doomed."
He doesn't know how he will die but he has seen that he will die and he has accepted his future. So he lay on the ground waiting for his death. He can see no way out of this so he will do nothing. His belief in the certainty of his visions of the future has made him give up without resistance.
Aeternus's face would have scowled if his crystal skin were flexible enough. He has gotten a way to kill the god of fate but his anger and bitterness have only increased. The god of fate intends to rob him of the joy of killing him. Killing the god of fate now without any resistance will be no different from killing a very powerful vegetable.
That wouldn't stop him though. He glared at his very willing enemy as he swung his claymore. This time, a black skull with five horns came out. The skull cackled madly before locking on to the unmoving god of fate and flying to him. The god of fate didn't move at all and was consumed by the skull. There was a very large explosion. It created shockwaves throughout the divine plane. A towering pillar of darkness rose from the point of the explosion and spread outwards.
It took a while for the pillar to disperse. When it did, a large white shiny core and a golden core appeared in the location of the god of fate. It signifies the death of the god of fate. The large white core is the Authority of The Celestial Supreme and the other is his Godhood. These two loots are very precious but Aeternus is not happy. In fact, he is filled with more bitterness.
He expected the god of fate to move when his moment of death actually came. Aeternus didn't expect him to be so resigned to his fate. He was waiting to see the god of fate jump up to defend itself in the face of death. Who can see death coming and do nothing? Apparently, the god of fate can.
He cursed at his dead foe. "Foolish guy. He could have struggled a bit."
Any clone of Legion would have struggled in the face of certain death. They believe it is not death if you're still alive and it is not certain until it has happened. The god of fate believed otherwise. He didn't struggle at all. His struggle would have been futile and useless. Yet, it would have been entertaining.
There's no way he can survive a full blow from an attack with five different Authorities. Even if he did, Aeternus has more waiting for him. But he should have tried if only to give Aeternus the satisfaction of killing him. But he chose to rob Aeternus of that pleasure.
The god of fate thought he had erased all the karma between them. He was right but Aeternus has changed. He became able to dig up the past so he can recreate a particular attack with a lot of ties to the god of fate. That attack also has the god of fate's authority and the Authority of the Celestial Supreme within it. They ensured a connection and a lock-on to the god of fate. He couldn't have escaped his fate no matter how he tried.
Aeternus muttered as he grabbed the two loot. "Karma is a bitch."
Karma is never straightforward at most times. Action produces equal and opposite reactions. In this world, action can create a much larger reaction and the reaction itself can create ripples that spread and affect future events. Karma will try to screw you over even if you take care of the immediate reaction. But one thing is certain, once you have settled karma, then it can't do anything to you anymore. That's how it has always been. Never before has karma been dug up from the past.
The ability to copy past attacks was deemed redundant. It turns out that it is a good tool to dig up long-buried hatchets and ask for reparations twice. The god of fate settled the first round of Karma but he wasn't rich enough to afford the second round of settlement. Maybe he was. After all, Aeternus wanted his life and he gave it. So he did pay up.
Aeternus shook his head and returned to the tree father. He dropped the Celestial Authority to the tree father and left the plane with the Godhood of the god of fate. The Godhood of fate is not important to the tree father as much as the Authority of the Celestial Supreme.
Besides, fate might have a nasty consequence on the tree father. It might enforce some rules such as non-interference on the tree father. The tree father doesn't want to have to sequester himself away from the world all for partial immunity when it has been proved that strength remains supreme.
The tree father can't take another Godhood right now and Aeternus needs one for the creation of his plane in the abyss. So they split the loot and he resumed his journey to wage war on other planes. Other planes will have the pleasure to rue the day they met the short but mighty demon king.