Chapter Text
The falling ashes tell a story of a war greater than any battle fought in history. The sky cracked and bled red, the sun scorched angrily by day, the moon basking the bloodied land in cold darkness. New mountains arose, though they were made of flesh and broken weapons. Fires blazed and black smoke clouded the land, the fuel not wood or coal but the rotted remains of monsters, allies and foes alike.
Yet, this war raged on ceaselessly. Both gods and mortals alike stood together to combat the invading forces that came in like waves, significantly overwhelming them. The Tsaritsa, the Cryo Archon, foresaw this battle between Celestia and Teyvat long ago when she started her crusade that may last for however long it would take, but she did not foresee the true scale of catastrophe that the war would bring.
For while the seven nations stood together under her banner to fight for survival— morals of the Fatui be damned— the true battle was fought between the Abyss and Celestia.
It was a disaster— no, a massacre. Celestia opened its gates to welcome its offenders with a barrage of magic projectiles that were even larger than the rock spears Rex Lapis had thrown in his prime. It cleared thousands upon thousands of Abyssal forces, numbers which Teyvat was convinced they would be crushed by a decisive victory within a few hours of a full-force invasion.
The Abyss Order attempted to ground Celestia, though before they could even set up their barrages they were immediately wiped out by the opposition. The battle would be over in minutes, until a bright light shot out of the chasm from which the Abyss Order entered the battlefield from.
Lumine was frozen in shock.
It was Aether. Or, better known by many, the Abyss Prince.
She had known he had regained a fraction of their original power during their time stuck in this world, however her heart dropped at the immense aura her twin displayed as he was suspended in the air, right in front of Celestia, engulfed in a brilliance that turned the night which everybody was standing in to the noon.
“I, the Abyss Prince,"
Lumine broke through the frozen troops of Mondstadt, pushing all other soldiers aside as she ran towards where her brother was. “Aether!”
“Stand before Celestia, its gods, its archons, and its subjects to allow you to bear witness."
“Ae—”
Lumine’s desperate scream was cut short when she was snatched off the battlefield by a blur of blue and azure. Trying to break free from her captor, she instinctively threw a punch where she figured their face would be when her wrist was grasped firmly as they came to a stop.
“Lumine.” starry pupils that held the deep dark of the ocean in them glowed in the shade of the rock they retreated towards.
Her eyes grew wide as she retrieved her fist. “Dain?” she clambered out of his hold. “Why did you stop me—”
“You will die if you step in right now.”
Her brows furrowed. “...What?”
“I challenge the Retainer of Heavenly Principles in a duel for the fate of this world."
The declaration suddenly threw the weight of its words physically onto its bystanders. Every mortal and monster began to shake in instinctive fear. Celestia did not need to say a word, they knew in their souls they had all been damned the moment the Prince of the Abyss raised his golden sword at the direction of the gates of Celestia.
Lumine gasped, raising her head to the sky as a light brighter than her brother’s began to engulf the sky as the gates of Celestia opened, blinding everyone who had laid their eyes upon it. Dainsleif clicked his tongue, grabbing Lumine’s arm and running the opposite direction of the epicenter of the light.
“Dain!” she tried to free herself from his vice grip. “Dain, I have to go up there!”
The man did not listen. Lumine’s eyes grew wide as she felt a strong thrum of energy emanate from Celestia. It reverberated her to the very core, shaking her very being, and she knew whatever Celestia was preparing was very bad news. Despite the blinding light that covered the land in pure white, she could see the faint shadows of the soldiers she stood with, and they were all running, screaming something incomprehensible. Weapons could be seen on the ground, discarded, forgotten.
“Let me go!”
A burst of Anemo was enough to push Dainsleif forwards and separate himself from Lumine as her wrist slipped from his hand. He stumbled and turned right around, wincing at the light and bringing his hand up to shield his eyes from it. “Lumine! No!”
She was running right back to where she wasn't supposed to be. Where anyone wasn’t supposed to be.
Aether, still holding his sword firmly at the emerging Retainer, stole a glance at the two figures below in the distance who were advancing towards him.
He recognized the Twilight Sword, chasing after his sister. Yelling something incomprehensible, perhaps telling Lumine to stop, to turn back. He chuckled inwardly. That’s the sister he knows. Ever so stubborn.
“The arrogance of man to laugh in the face of certain extinction.”
The small smile on his face disappeared as he finally saw the floating figure of the Retainer confronting him. She was looking down upon him, in an obvious show of contempt for him.
“The existence of your organization was a sin in of itself, one that we have allowed you to keep to entertain yourself. A mistake, that was. One that I will certainly rectify this time around while wiping this world clean of your trace.”
Anger surged through Aether’s veins as his grip on his sword tightened. The Retainer looking down upon him was one thing he could forgive, however Celestia taking his stance as a joke was another thing.
Raising his sword, he summoned all his power to infuse on his blade. A single strike to cut down the Retainer and Celestia, to be done with this once and for all. A crushing blow to force the gods to their knees and accept defeat in the face of their subjects.
“Your blood will be enough to wash this world clean of your lies!”
“AETHER!”
He heard nothing but the deafening screech of his blade as he brought it down upon the Retainer. He saw a tinge of yellow, and his eyes slowly turned in horror as Lumine was heading straight towards the trajectory of his blow.
The Retainer scoffed, before sending out a barrage of crimson cubes to the direction of his sister.
White, red, and purple clashed right in front of Lumine, combining and conflicting each other for a split second before repelling each other once and for all, intersecting fiercely that it covered everything in black for a moment, before exploding violently in a deafening roar.
The land they were on jumped, the sky fell, and the shockwave was so intense it even pushed Retainer away; Celestia as well. Aether wasted no time to wait for the smoke to clear. Bursting through the showering dirt with his blade glinting gold and white, his wings fluttered right in front of the Retainer’s face as he thrust his sword with all his might with a mighty scream.
The world fell still.