A Demon King Through The Worlds

"Great! But I warn you that it might hurt a little" Lucian smiled, before sticking his right index finger into her forehead and then injecting blood.

Receiving the demon king's blood, Mitsuri's body froze, before beginning to twitch.

Her veins swelling and her muscles contracting.

His heart exceeding 200 beats per minute, feeling like it was about to burst.

The internal pressure becoming so great that she felt like she was almost becoming a bomb.

A bomb that would explode sending blood everywhere.

The heat originating in the spine and being spread through her bones.

As if someone used a knife to create an opening, then poured molten iron into them.

And something similar actually happened, only it wasn't molten iron.

The demon king's blood used Mitsuri's veins to cross her entire body, and reaching each cell, it transformed them from the inside out.

Clearly, in this not very gentle process, some cells do not adapt and the mutations get out of control, killing them.

This is why some people die in this process, especially those who swell until they burst because they have developed massive tumors.

"Argh!!!" Regaining the ability to make sounds, Mitsuri let out a painful roar.

At the sound of this roar birds took flight, squirrels ran to their holes, and insects fell motionless, all terrified not only by the sound, but also by the power that came behind it.

She certainly would have said something if it weren't for the fact that the agony that filled her mind even prevented her from thinking.

Mitsuri's movements became more intense, pain-filled grunts sounding, before finally ceasing entirely.

There she was, standing still.

After a few seconds, she raised her head, her vertical eyes staring at Lucian.

"You call that little?!? I felt like I was dying!" Exasperatedly shouted Mitsuri, she had never felt such horrendous pain before.

"I think that's why many end up forgetting their memories before the transformation" Lucian commented, shrugging.

"Or because they 'die' during the process"

Of course, he was referring to a more figurative death, the death of who the person previously was.

"Anyway, you managed to come out of your 'cocoon', how do you feel now?"

"I feel like I can fly far with these 'wings'" Mitsuri replied, continuing the analogy with butterflies.

The process of "coming out of the cocoon" was painful, but now she could "fly" far.

It's like they say "no pain, no gain".

Just like a caterpillar that transformed and started to have wings, it now had tens of times greater strength, speed and regeneration.

Demon slayers use techniques to fight, demons usually just use brute force.

But when both come together...

Kokushibo and Akaza serve as examples.

In addition, all demons who knew any breathing techniques became higher moons.

So Mitsuri's strength could be imagined.

"Come, I'll take you to the demon's base, the infinity castle." Lucian snapped his fingers and a door opened.

Upon seeing him walking through the door, Mitsuri quickly followed him.

Being amazed the next moment.

"So amazing!!" She said, jumping up and down as she observed the peculiar architecture of the infinity castle.

"You can walk around the castle if you want" Lucian smiled, looking at Mitsuri who looked like a curious child.

"Yay!" Exclaimed Mitsuri, simply starting to walk around.

'Let her have some fun. She needs to adapt completely.' Lucian thought, looking at Mitsuri who was moving further and further away.

He knew that she was still not completely loyal, and even though she tried to appear normal on the outside, she was still suffering from several internal conflicts.

And he wasn't afraid of her getting lost in this vast space, after all Nakime has control over the entire infinity castle.

One touch of her biwa and Mitsuri will be brought back.

"Nakime, I will give you an update." Lucian said, stretching his arm towards Nakime.

"Update?" Nakime looked confused, both Muzan and Lucian gave their blood to their subordinates, but neither of them ever referred to it as an upgrade.

"Yes, I'm over the sun, and that's a great update." Lucian replied, a touch of pride appearing on his face as he said this.

"I thank you for such kindness" Nakime quickly thanked, getting on one knee in front of Lucian.

"No need for so much etiquette, act more casual." Lucian commented, before injecting her with blood.

The process was much simpler compared to Lucian who had to evolve under the influence of the blue spider lily and Mitsuri who was transformed from a human.

Both faced some resistance. Lucian had to generate more gene chains, while Mitsuri's genes were altered to become those of a demon.

However, with Nakime, she was already a demon and Lucian just added a few more things in a very smooth process.

"...I feel like i have been sublimated..."

"Because you did, you became a 'complete demon', thus overcoming all the problems brought by 'incompleteness'."

This thought was not wrong, after all, the treatment that turned Muzan into a demon was stopped halfway through, because of the doctor's death.

"By the way, keep your face like this, I prefer it this way." Lucian said, lifting Nakime's bangs, revealing a beautiful face.

He had restored her face to "normal" instead of a single eye.

Nakime just nodded slightly, her emotions as unreadable as ever.

"Send me to the Kamado house" Lucian commanded.

With the echo of the biwa, Lucian soon disappeared, leaving only Nakime in the empty space.

She then touched her face, a certain emotion running through her mind.

"...So he likes it like this..."

It had been a long time since she felt something like this, perhaps only when she had just married her husband, before he lost himself in the game.

...Before she killed him.

Her heart soon returned to being as calm as an uninhabited lake.

On the other hand, Lucian was already in front of Kie again.

"Have you prepared for the transformation yet?" He asked her.

"Yes, I'm ready!" Nodded Kie, she had spent the day firming up her resolve.

"Are you sure? The process will be highly painful, although this pain will only make you stronger in the future." Lucian warned, some concern appearing in his tone.

He knew that Mitsuri wouldn't have much trouble going through the transformation, after all she was a hashira.

And to some extent, he was taking revenge.

But Kie is just a normal housewife, would she be able to take this pain? Plus she was one of his wives, so he was worried.