Roughly 10 years ago.

"Hmm... Did I miss Ain perhaps...?"

Waiting in front of a well was a 5-year-old Mika. He originally made an appointment to meet up with Ain Sacra at the village’s well in the center to gather herbs together. However, he was the first to arrive.

"Or maybe she’s waiting near the forest already...?" Mika wondered.

And without a care for the world, he skipped to the forest outside the village.

The people in the village mentioned that the forest was dangerous since a few weeks ago but Mika and the Sacra siblings still sneaked out to hang out there or to gather herbs.

Of course, they knew where it was dangerous so they were mostly at the forest’s edges where the monsters would not appear.

"Help!"

"?!"

Once Mika arrived, he heard a young girl’s scream from the depths of the forest.

And without thinking, he rushed right into the forest, forgetting about the dangerous monsters there.

"Help!"

The girl was close so Mika turned his head everywhere, looking for a person’s trace.

"Help."

Mika flinched when he heard that word being whispered into his ear. However, it did not sound urgent anymore, instead, the tone sounded eerie and calm.

He turned around to see who it was only to see a young girl his age.

She had black hair, styled in a bobcut, and round black eyes. Her wide grin sent shivers and the fact that she only wore a white oversized shirt in a dark forest did not help calm Mika down.

With shaking legs and jaw, Mika fell on his butt, crawling away from her. He was so struck with fear that he could not even utter a sound.

"Didn’t your parents tell you to avoid the forest?" that girl remarked amusedly.

She slowly reached out to Mika, who in turn, gathered all his adrenaline and ran away clumsily.

"..."

Indifferently, she looked at him.

"What an idiot..." she sighed.

She did not go after him as his fate was sealed.

In the direction he ran was a horde of strong monsters. Even she, as a low C-rank demon, had problems facing them.

Still, she was slightly interested in seeing how Mika would fare against them so she spread her black wings and flew after him while paying attention to her surroundings.

Meanwhile, Mika still ran.

"Ugh!"

Until he fell on his face after tripping on roots. However, he quickly got up and ran further. And soon, it turned darker and colder the deeper he was in the forest.

He slowed down his space and eventually came to a halt.

"..."

His breathing was ragged. His throat hurt. His body was hot and sweat a lot.

He had no idea where he was. He ran aimlessly all the time until he found himself at a bizarre spot.

He was deep in the forest, an area where no one would voluntarily spend one’s time, and yet, there were traces of someone camping here as a small campfire was lit up.

However, he noticed the sound of multiple creatures approaching him slowly.

Instinctively, Mika approached the camp with his back as he paid attention to the incoming monsters.

Mika took a fast glance at the camp but there was no one there.

"...?"

But he saw a sword stuck in the ground.

He gulped down his saliva.

The 5-year-old Mika reached out to the stuck sword as his guts told him to find a way to survive.

In his mind, Mika thought that the monsters would surely get scared if Mika pointed such a strong and fancy-looking sword at them.

"Hngh!!!"

However, even though he was pulling with both hands, the white-bladed sword with a golden hilt would not budge from its spot.

"Haa... Haa..."

Mika took a short break after he lost his strength. But he had to realize soon that he could not waste time when wolf-type monsters appeared from the bushes. Even the girl from back then was in sight again.

Still, he had no idea how to pull the sword out.

"If only I had more power...!" he lamented exhaustedly.

"You want power?"

"?!"

Suddenly, someone patted Mika’s head from behind.

The hand was big and the voice gentle.

"M-mister, is that your sword...?" Mika asked nervously.

He was scared that the person mistook Mika for a thief.

"..."

The person did not answer.

And in the meantime, the monsters and the girl stopped in their tracks.

"N-no way... What is he d-doing here...?" she muttered in great shock.

Mika looked around his body because he was suddenly surrounded by light particles.

"Seems like you have potential." the man behind Mika stated slightly happily.

"H-huh...?"

Mika could not see the man’s face and whenever he tried to turn to him, the man’s hand would make sure that Mika’s gaze would be directed to the sword in front of him.

"What is your name?"

"M-Mika Elbar..."

The man chuckled.

"Mika, huh? That is a great name."

The more time passed, the more nervous Mika was. He was surrounded by monsters and two suspicious individuals in a dark place far away from his parents.

"Do you want me to give you power to defeat your enemies?" the man asked with a smile on his face.

"I-I wouldn’t mind if you were to defeat them for me though... D-Dad told me that I should seek help if possible when I encounter monsters..." Mika replied sheepishly.

"..."

The man tilted his head baffledly.

"W-well... I certainly did not expect that response... But that sounds logical I guess..." he muttered pensively.

"I apologize but I cannot fight."

"W-what...?!"

Mika was also shocked to hear that.

"B-but you have such a cool sword! Aren’t you a great fighter then?!"

"Do you want it?"

"..."

Mika remained silent for a moment.

"You see, we can either survive if you pick up this sword or we die together."

"T-that’s unfair...! I’m just a kid!"

"Just see this as an opportunity to grow up sooner than the other kids."

The wolf monsters cautiously closed in on them.

"Do not worry. I will guide you until you do not need me anymore."

"..."

Mika was grumbling a little until he finally gave his answer.

"I-I want power...!"

"Good answer." the man said relievedly.

"Put your hands on the sword and try to pull it out again. Trust me, this time it will work."

Mika nodded his head nervously.

And this time, the sword really moved. The further Mika pulled it out from the soil, the brighter the light on the blade shone.

For the brink of a second, the whole place was illuminated by that light.

"I-I did it!" Mika stated joyfully with fascinated eyes.

He turned around to show the man the sword he was holding but there was no one.

And when he turned around and looked at the sword, he noticed a change in the sword.

"Huh?!"

Mika held a rusty sword that could not even leave a cut on anything.

"What happened...?" the demon girl wondered sternly, watching the confused Mika from above.

She sighed.

"I should just kill him before anything funny happens...!"

Thus, she prepared herself to launch an attack on Mika.

[Mika, listen.]

"?!"

Hectically, Mika shook his head.

"A-a voice in my head...?!"

[We do not have time for that now. Focus on your opponent.]

"!"

Mika recognized the incoming threat.

[Now, try to visualize yourself with blonde hair.]

"B-blonde hair...?"

[Just do it.]

"O-okay!"

[In addition, try to visualize yourself with blue eyes.]

"Blue eyes...!"

While closing his eyes to focus more, Mika followed the instructions.

He held the rusty sword with both hands in front of him.

[White pupils.]

"White pupils..."

The demon flew towards Mika.

[Those pupils are shaped like a cross.]

"Okay...?"

That girl’s hand was retracted as she attempted to pierce Mika with her long nails.

[And now, try to imagine yourself with a bright halo above your head.]

Mika nodded firmly.

Then, light filled the area again.

"!"

The girl halted her movements as she got blinded.

"Hngh!!!"

In front of her was Mika but now he had the appearance of her kin’s archenemy.

He looked like an angel.

"You’re kidding me..." she muttered dumbfoundedly.

Her gaze then wandered down to Mika’s sword which apparently turned into Excalibur.

However, Mika was struggling to hold it due to its weight and size. The white blade was mostly lying on the dirty soil.

[...]

The voice of the person giving Mika the instructions sighed.

[I have no choice then. This will be my first time trying this but let me take over, Mika.]

"W-what do you mean by that...?"

[Entrust your body to me and I will promise to get you out of here.]

"E-entrust my body...?!"

[It will not be for a long time. Or do you want to die here?]

"..."

Mika was hesitating.

"C-can I at least know your name...?" he asked softly.

The person sighed again.

[We have no time for introductions. Just call me...]

While he was pondering, the demon charged at Mika again.

[Call me system for now.]