Reincarnated With The Strongest System

Unknown to William, his fight with the God of Death was being watched by several Gods in the Temple of the Ten Thousand Gods.

His Patron God, Gavin, and those who had always supported the Half-Elf like Issei, Lily, David, and the rest of the Gods who had a good impression of him, watched the battle with varying expressions on their faces.

Some found this battle amusing, while others had started to bet with each other on who would win the battle.

Surprisingly, all of them sided with Thanatos, making the bet void because no one wanted to bet on the Half-Elf, who was currently fighting a desperate battle against one of the strongest Gods in existence.

Celine watched this battle from the Elysian Fields as she hummed a lullaby to her baby, who had just finished breastfeeding.

Lyssa, the Goddess of Wrath, looked fondly at Celine's baby boy before shifting her gaze to the battle that was happening on the Fourth Layer of the Underworld.

'Aren't you worried?' Lyssa asked using telepathy as she glanced at Celine who was still humming a song.

Celine shook her head as she continued to hum her lullaby.

'William might not win against Thanatos, but he wouldn't lose to him either,' Celine replied.

'Oh? You believe in him that much.'

'Of course. I was the one who taught him how to fight, afterall. Besides...'

The beautiful Elf caressed the side of her baby's face before shifting her gaze to the projection of the battle in front of her.

'He knows that he is now a father,' Celine stated. 'He will not allow himself to kick the bucket before he can even hold his child.'

Lyssa smiled because she didn't know where Celine's blind confidence was coming from.

However, for some reason she found herself agreeing with her, as she looked at the Elf boy that was wrapped up in a light blanket.

Celine's child was a full-blooded elf, with one major distinction. He had red hair like his father, and purple eyes like his mother.

After being born, Celine had given him a name, which she, and William had both agreed upon if the child she gave birth to was a boy.

Ciel Von Ainsworth.

He was William's firstborn, and would become the elder brother of the kids that would be born after. Because of this, Celine vowed that she would raise her child properly, so that he would grow up to become a person who would pave the way for the next generation.

"Your father is fighting right now, Ciel," Celine muttered as she lovingly held her child. "Let's cheer for him, okay?"

As if responding to his mother's words, Ciel opened his eyes and smiled at her, making Celine's and Lyssa's heart melt, temporarily forgetting that the father of the baby in front of them was fighting with his life on the line, against the God of Death, who ruled the Underworld with an iron fist.

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"World End Tempest!" William smashed his right palm on Thanatos chest, making the latter take a step back before punching WIlliam's chest, which sent the latter smashing towards the wall of the Fourth Layer.

'Even the power of Rule Breaker is not enough to deal damage to him,' William thought as he wiped the blood away from the corner of his lips. 'I need a stronger attack.'

The Half-Elf had already tried all of his attacks against Thanatos and none of them worked.

Stormcaller, and Soleil only managed to give him a slight bruise, which healed in a matter of seconds.

His special attack, World End Tempest, wasn't good either. At most, it only tickled Thanatos, and made him take a step back due to the force behind the attack.

'What's next?' William dodged frantically as the God of Death once again unleashed several Death Rays, only this time, the Death Rays were as big as an electric pole, disintegrating everything that it touched.

William had repeatedly tried to call out to the wooden staff in his hands, but it was to no avail.

When he was back in the alternative world of Camelot, he was able to unlock the wooden staff's true form, allowing him to split Merlin's domain in half, and make Lancelot lose consciousness during their exchange.

The Half-Elf believed that if he could use that attack again, he would be able to deal significant damage to the God of Death, making the latter feel a world of pain.

Unfortunately, the wooden staff remained dormant no matter what kind of method he tried.

William instinctively felt that the staff would only respond to him when his soul had fully recovered, allowing him to wield the weapon that could make even Gods fear for their safety.

"I guess you're not ready yet."

A voice spoke inside William's mind, making the Half-Elf frown.

Suddenly, the scenery around him changed.

He was no longer inside the Fourth Layer of the Underworld, but in a place with a clear blue sky, and an ocean that expanded as far as the eyes could see.

William knew that he was inside his Sea of Consciousness, and right now, he was looking at the silver-haired Einherjar, who was wearing the battle regalia that he had worn during the battle of Ragnarok.

"Although I have recovered, we still haven't completely merged together," the Einherjar William said. "But, before we do, can I ask you a question?"

William nodded as he looked at the past him, who had kept his memories of Asgard during his many lifetimes.

The soul that had slept within the Bell of Anthanasia, remained uncorrupted by Darkness, and had fought against Ahriman, when the Dark Prince had gone berserk during his fight against the Heir of Darkness.

"Why do you fight?" the Einherjar William asked.

"Isn't that question a bit strange?" William asked back. "Why ask me the obvious? You are me, and I am you. You know everything about me, so you already know the answer to this question."

The Einherjar William smiled. "I want to hear it from your lips. That is the only way for the two of us to once again become one. When you were corrupted by Darkness, our resonance with each other waned. Although we still share the same goals, our viewpoints have changed."

"Isn't that normal?" William replied. "The only permanent thing in this world is change. If we stand still, nothing will change. This is why we must move forward and do the things we have to do, for the sake of the people who believe in us."

The Einherjar William walked towards the Half-Elf until they were only an arm's length away from each other.

"I'll ask again, why do you fight?" The Einherjar William stared at the Half-Elf with a smile. "Tell me why."

William took a deep breath before extending his fist, until it rested on the Einherjar's chest.

"To keep the promises that we failed to keep thousands of years ago," William replied. "And to keep the promises we made in this lifetime. We cannot turn back time, but we can strive, with everything we have, to prevent the same thing from happening again."

The Half-Elf then retracted his arm before pounding his own chest with conviction.

"Even in the face of great adversities," William said.

"Even against the whims of Fate," the Einherjar William smiled before he, too, pounded his chest with a fist.

"Even when facing our greatest fears."

"And the challenges we've overcome through the years."

"Even when there is no hope in sight."

"We will make our stand and fight."

"And keep the promises we have made."

"For those whose love we were bound to take."

"In a world where everything is grieving."

"It is proof that we are still living."

The Einherjar William laughed as he turned into particles of light and merged with the Half-Elf, becoming truly whole once again and allowing the half of his soul he still had to merge completely.

As the two parts finished merging together, the Einherjar William gave the Half-Elf some parting words.

"Do not shun our Origin, for that is what we truly are," the Einherjar said softly. "Accept the power that lies within, and fight the flames that slayed the living."

The sound of a bell echoed within the Fourth Layer of the Underworld, as William's body radiated a silvery light.

His golden eyes gazed steadily at the God of Death, who started to unleash his heavenly might.

"Try not to die, Father," William said as he gathered the silver light in his hands, turning it into a sword. "I still can't control this power, so I apologize in advance if I accidentally kill you."

William knew that with only half of his soul, he could only use this ability once a day.

Thanatos firmly gripped his weapon as he stared at the Half-Elf whose silvery radiance was expanding continuously.

For the first time in his thousands of years of life, Thanatos felt that he was now facing something that truly had the power...

To kill him.