The mortal combat between the two grew increasingly vicious. While they had initially paid attention to the damage their bodies sustained, after both converted their internal energy to the nature of Abundance, they no longer cared about the wounds to their bodies and souls. They began a long and grueling war of attrition, an endless cycle of mutual torment with no clear end in sight.
You hack me into pieces, and I will cleave you into chunks. The battle between them had devolved completely into a war of attrition over their internal energy. However, due to the nature of spacetime and their own unique properties, they could endlessly draw upon the Imaginary Energy or Honkai Energy in their surroundings to replenish themselves.
Even so, after several more rounds, Xin Yu seized an opportunity to drag the Heart-Demon down into the Sea of Quanta with him. There, he no longer needed to worry about the shockwaves of their battle harming the innocent or causing irreparable destruction. And so, he completely let loose.
But at the same time, both were now able to draw upon the nigh-infinite quantum energy of the Sea of Quanta to replenish their own energy consumption. Thus, the war of attrition over their energy transformed from merely "long" to "virtually infinite."
All that was left for them to compete over was their spirit and will. Whoever was the first to break under this cruel, mutual execution would be the one to lose.
This led to a scene in a future world where Kevin, still in the Sea of Quanta, watched as two monsters, whose destructive power was absolutely on a planetary level, fought to the death in its depths. Even from an extremely remote location, in a peculiar place like the Sea of Quanta where direction was almost meaningless, he could feel the waves of fury radiating from afar.
Sensing that immense power, he thought about his current weakened self—no, even if he were at his peak, he likely stood no chance against monsters of this caliber.
The slaughter between the Heart-Demon and Xin Yu became fixed in the depths of the Sea of Quanta. Both had lost all expression, all words, as they threw themselves body and soul into the battle.
The pain of a pulverized body gradually became numb. The agony of a sundered soul was slowly adapted to. Their tolerance for pain was rapidly ascending in a short amount of time.
The damage to their souls and bodies was healed in an instant, and their depleted energy was replenished in a flash by the teeming Sea of Quanta.
This act, akin to endlessly detonating nuclear bombs in the ocean, naturally attracted the attention of many beings.
Some unique life forms from the deepest parts of the Sea of Quanta noticed these two peculiar intruders. However, after witnessing their terrifyingly savage combat and their monstrous regenerative abilities, all these creatures silently distanced themselves from that area.
It wasn't that the gap in their energy levels was too great, but that the various spacetime manipulations those two performed were enough to make these native life forms' scalps tingle with fear.
Because the two were, in essence, the same person, there was almost no difference in their abilities. When they used their powers against each other, even if one gained an upper hand at first, the advantage would soon be nullified as the other analyzed and countered it. The damage caused would not be significant.
That was why they had resorted to the most primitive form of combat: a duel of swords.
This protracted battle had lasted for an unknown amount of time. Perhaps it had been a mere ten and a half days, or perhaps several years had already passed.
In the Sea of Quanta, where the concept of time was blurred, the duration of this battle had become impossible to calculate.
In any case, after a long time of unknown duration had passed, the slaughter between the two came to a halt.
"Hah… hah… how long have we been fighting? Why do I feel like it's been a hundred years?"
The Heart-Demon still held his longsword, but the hand gripping it was trembling slightly. His breathing was ragged, and even his once pure-black eyes had dimmed, now tinged with gray.
"It has been approximately twenty-five years and six months. It has been twenty-five and a half years since we fell into the Sea of Quanta."
Xin Yu's tone was still calm, but his aura had become extremely unstable—at one moment holy, the next intimate, then bizarrely demonic. It was enough to make one's blood run cold.
"After fighting for so many years, my will and spirit can't take it anymore. I'm tired now, so tired I just want to sleep. I don't want to fight anymore."
The Heart-Demon exhaled a turbid breath and loosened his grip on his longsword. The blade dissipated into specks of gray-white light as it fell.
As if his exhaustion had completely robbed him of the strength to stand, he collapsed into a sitting position in the void, gasping for air.
After twenty-five and a half years of this, the Heart-Demon and Xin Yu had endured their bodies being constantly destroyed, their souls constantly severed, their lifespans constantly drained, and their minds and spirits constantly worn down in a series of torments.
Having fought so viciously for twenty-five and a half years, the Heart-Demon truly felt his mind and soul were utterly exhausted. Even his own form was beginning to blur.
"But I can't just give up like this. Our ideals are destined to be opposed. There is no way I can reconcile with you and merge back into one. I don't pursue a better world like you do; I just want to become strong enough to satisfy myself. Therefore, our opposing ideals have determined that one of us must die."
The Heart-Demon looked at Xin Yu, who remained standing, ever-ready for battle, and couldn't help but sigh.
He had hoped that this act would slightly lower Xin Yu's guard, giving him an opening for a sneak attack. He never expected that, even now, when both were running on fumes, his opponent would remain so vigilant.
"Let's decide this with one final move. I will bet everything I have—all my remaining lifespan, my very form, and all my energy will be burned to ashes to unleash my strongest and final strike. If you can take this blow and live, then you win. If you die, I will be reborn from this act."
"But no matter what, this is the final battle."
"Farewell forever, Xin Yu."
"Goodbye, me."
Hearing Xin Yu's reply, a slight smile appeared on the Heart-Demon's face. Then, a pure white flame ignited upon his body.
He pushed himself back to his feet. His right hand plunged into his own body and pulled out his spine, which transformed into a bone-white greatsword.
He gripped the bone-white greatsword with both hands, feeling the agony brought by the flames that were burning his very existence to ash. Yet, he still smiled. Then, he gently swung the most brilliant, and perhaps the final, sword strike of his life.
At that moment, all across the cosmos, every Emissary and Aeon raised their heads to look toward the distant horizon.
Far away, beyond the Milky Way, even beyond the wall built by the Amber Lord, a minuscule white line, no more than ten meters wide, slowly appeared.
Then, every living being in the universe heard the sound of a mirror shattering.
[A being on the same level as an Aeon, but who is not an Aeon, has been born.]
In that instant, every being came to cognize this single sentence.