During the demon king's prime, before the birth of the hero, he spoke to a traveling oracle. She had walked up to the throne, bowed before his might, and loudly proclaimed, "Oh Great Terror, your reign will crumble with the birth of a hero!" Ceasar scoffed at the time and she left with, "Do as you will."
When the first of his generals had perished, he thought it was but a fluke. Then, the second one died as well.
By this time, he had heard of many more exploits that the perpetrator had done but still didn't take the prophecy seriously.
However, after he finally saw him in action, stabbing Ceasar's third-born son, he felt a deep connection with the assailant and could only think of one word, "hero."
Ever since he had been preparing to defeat the hero. He may have been a mere human, but Ceasar instinctively realized the threat that he was.
He wasn't a fool, especially after many bouts resulting in draws, or at least the hero's survival, he knew he had to create something monstrous.
So, as the fierce war raged, he secretly and methodically, designed a weapon to be feared. A weapon to crush all opposition, including the hero.
Ceasar's last resort was forged with the sacrifices of numerous species. Everything and everyone were materials. He even used his eldest daughter and son. It was their honor after all.
After many years, it was finished, another body from the abyss, the place with nothing but darkness. Ceasar had found access to it with his rise to prominence, and it seemed like the perfect place to house his masterpiece.
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When the ginormous, hulking Ceasar crawled out of the chasm, his head crashed through the ceiling, revealing the crescent moon shining down on the invaded castle.
The army led by Allen had nearly finished off the remnants of the Demon King's troops as they saw the terrifying figure, whose movements destroyed parts of the castle.
They had become so confident, but that was before Ceasar revealed his trump card. Their instincts screamed at them to run away, and those weak enough, couldn't even manage that much as they grew stiff.
Allen quickly rushed at the unconscious elf princess, scooping her up in his arms and exiting the destroyed room. As he passed by his soldiers, he yelled for them to run. Ceasar was too great an enemy for them to be close to.
A mass exodus as fast as they entered ensued, Allen and the few elemental spirits destroying rubble that had been flung at numerous people and escorting the injured away.
Ceasar's insane laugh echoed in the night sky. He was relishing the mayhem. When the majority of the army retreated into the woods, Allen carefully placed Cairo in front of a priest whispering, "Save her," before running off toward the towering Demon King.
As Ceasar stood atop his half-destroyed castle, he scanned the rubble surrounding him and the figures running into the woods and sighed, "It feels so insignificant now. To think, the fortress I was so proud of was destroyed so easily. At least I'm the one responsible."
His eyes landed on one of his generals as she lay on cracked stone, bloodied, indicative of severe injuries. He grabbed her by the scruff of her neck, his finger the size of it, and raised her to his eye level.
She was Lapis Anguis, the queen of the medusa species, and she specifically, could turn a normal human to stone in seconds with a glance.
Her hair of snakes had been cut off and sword slashes were over both eyes, causing blindness. Spitting out blood, she stammered out in barely a whisper, "I-is that y-you? Avenge m-me and m-my p-precious hair."
Her breathing became erratic when Ceasar looked past her to see a blue light dashing in his direction. He dropped Lapis into his hand and crushed her, blood dripping down to the destruction below.
The blue light jumped in the air, revealing Allen covered in mana swinging his sword at Ceasar's large neck. Ceasar activated his red aura which knocked Allen out of the air.
He landed, stabbing his sword into the rubble, and slashed at Ceasar's ankle. Mana ejected from the sword and cut through the bloodthirsty aura, causing a gap.
Ceasar tried to stomp on Allen but was dodged as he stabbed his sword through his ankle, exploding the bone into powder. He fell to his knee, grimacing, and his aura intensified.
Allen fell, staggered, as Ceasar, while falling, aimed his hand at the stiff hero. His hand smashed into Allen's body, causing a hole in the ground.
Allen barely stopped the hand from crushing him when he activated his sword and exploded his mana from under it. Ceasar pushed down harder and directed his aura into his hand, putting vehement pressure on Allen and making his hold weaker.
After a minute of struggling to hang on, a faraway wind spirit shot a wind blade at Ceasar's eye. Focusing his aura on his hand, he failed to block the attack, and the blade blinded his left eye.
His aura significantly weakened as he moved his hand slightly upward from the pain which allowed Allen enough time and strength to cut off his pointer finger and break out of the hold.
Ceasar began assaulting the ground with a barrage of punches, trying to halt the evasive Allen, but the hero was too swift as he slashed into his other ankle, causing Ceasar to fall on his other knee, and making his breathing more erratic.
The spectating army cheered at the weakened monstrosity, believing that Allen could achieve victory. However, the hero's slow movements said otherwise as he spat out blood.
"I-I'm not sure how much longer I can hold on," Allen quietly said to himself, sputtering for breath. 'I might have to use that,' he thought as he looked up at the fatigued and bloodied Demon King.
Allen's state was exceedingly strong but was also hard to maintain, taking years off of his life and greatly damaging his body. He did have one more trump card, but hoped he didn't have to use it.
Allen jumped up firing slashes of mana at Ceasar's body as he rose. Ceasar's aura blocked most of them but some managed to cut into his skin, damaging him more and more.
When Allen was at eye level with Ceasar, aura, and mana pulsed, pushing against each other, neither getting the advantage. It was a beautiful spectacle to the onlookers as it was a wave of vibrant blue and bloody red.
After what seemed like hours of a stalemate, Allen's sword pierced through, creating an opening, and stabbed into Ceasar's other eye.
He roared with rage, the wound only causing his aura to strengthen as he lost all reason. Ceasar grabbed ahold of his horns, ripped them out of his head, and covered them in aura before chucking them at the army.
The horns had caused two massive holes in the woods, killing many of the soldiers, but because of this attack, Allen could break more of Ceasar's aura, allowing his sword to stab into his neck.
Blood spurted out like a fountain, but the Demon King only ignored it as he tried to bite Allen with his shark teeth. The teeth bit into his wrist, but before the hand could be bitten off, mana was directed toward it as Allen stuck his arm further up the mouth.
Mana exploded down Ceasar's throat, causing him to let go of Allen and smoke to rise through his mouth. Allen fell, his sword stuck in Ceasar's neck.
The Demon King punched Allen with his giant fist and started to pummel him. He only survived by blocking half of the punches with mana and because the attacks weren't as strong due to Ceasar's weakened state.
As Ceasar went to finish Allen off with one last punch, his arm fell weakly. Allen lay dazed, coughing out blood, his mana diminishing.
He lazily looked up to see Ceasar struggle to move yet unable to and his sword falling next to him.
'I have to use it!" he thought, tightly gripping the sword. His mana flared up again as Allen started looking older and older, wrinkles slowly appearing on his face.
His last resort was sacrificing his youth for mana. A blue beam, brighter than anything anyone had seen before, shot upward from the sword's tip as he stayed mangled.
Ceasar heard and saw nothing as the beam increased in magnitude and encompassed him. Then, "boom!" The tower of mana exploded, blowing Ceasar into nothing but blue particles scattering in the wind.
Allen lightly smiled. It was finally over. He had put a stop to the decades-long war, and Ceasar, the terrible Demon King, had been defeated. Although he was now in his fifties, twenty years older than when he started this invasion, he didn't regret it at all.
Despite his jubilance, he felt a pain as if his family had been killed again. "To feel a sort of kinship with Ceasar," Allen whispered.
"Ha." he chuckled before falling unconscious.
A silver-armored knight with a golden plate attached to his shoulder galloped out of the woods on horseback and stopped, hovering over Allen, followed by other soldiers behind him. He took off his helmet, revealing a middle-aged man with a buzz cut and a scar over his left, brown eye.
He dismounted his horse, took off of one his gloves, and placed his fingers at Allen's neck, checking for a pulse.
He sighed in relief as he yelled in a gruff voice, gripping the handle of his sheathed sword with a dragon insignia on the pommel, "Take our savior to a priest! He takes priority! Also, make sure to hunt down any demons that may be left, taking extra precautions when searching the intact part of the castle!"
A chorus of voices shouted out, "Yes Captain William!"
He looked up at the beautiful night sky and muttered sternly with a twinge of happiness, "The era of the Demon King is no more."