With Tanjiro's matter settled, that left Nezuko.
Of course, Nezuko was already very cute, but seeing her with her hair tied up and wearing a simple kimono, it always felt like something was missing.
So, Kaito took out a bottle containing a pale gold liquid that he had pulled from the gacha that night.
[Demon King Ability Potion] (A-Class)
Its effect was to allow a person to awaken (not acquire) the abilities of a Demon King, with no side effects or limitations.
The advantage was gaining a lifespan and strength surpassing that of an ordinary Demon King; the disadvantage was that the strength of the Demon King's abilities depended on the individual.
After all, this Demon King potion was less about turning someone into a Demon and more about causing genetic changes.
It was similar to the T-Virus.
Some people who used the T-Virus became incredibly weak, even turning into zombies.
But the protagonist, Alice, used the T-Virus and became overwhelmingly powerful, capable of cutting through a sea of zombies.
This A-Class Demon King Ability Potion was like that.
The reason it was a potion rather than Demon King's blood was precisely because of this.
"Kaito-nii, what is this?"
Faced with a suddenly presented beautiful bottle, Nezuko tilted her head adorably in confusion.
"Hehe, this is a gift for you."
"A gift for me? Kaito-nii, what is it? Is it a drink?"
The pale gold liquid looked rather impressive.
Nezuko curiously took the Demon King Ability Potion, removed the wooden stopper, and sniffed it, only detecting a faint floral scent?
"Is this drinkable?"
"Of course, it is drinkable."
Kaito didn't directly explain its specific abilities, preferring to let her drink it first.
After all, she would need to be unconscious for a while after drinking it. He could explain things to Kie and the others then.
He was also afraid Nezuko might refuse if she knew she would turn into a Demon King.
So, it was easier to let her drink it first.
Since the strength and effect of the ability depended on the individual, it was quite similar to the situation where Nezuko was injected with Muzan's Demon Blood.
The end result would be Nezuko turning into the Demon Nezuko from the original work.
Her abilities would be identical, but her strength would far surpass the original. Moreover, she wouldn't have the limitations of fearing sunlight or needing to eat humans.
She also wouldn't fear attacks from Nichirin Blades, and any injuries she sustained would heal rapidly.
To kill her, one would either need an overwhelmingly powerful attack to annihilate her in one go, or exhaust her stamina so she couldn't recover!
That was the ranking of the A-Class Demon King Ability Potion.
Calling it strong was accurate; after all, being ranked A-Class meant it was not weak.
As for Muzan...
In the final battle, he was probably around A-Class as well?
If that were the case, Yoriichi was also quite strong, capable of instantly defeating Muzan. Even though Muzan was indeed very weak at that time.
As for his original weapon being only D-Class, that was naturally because the weapon strength in this world wasn't particularly high.
Not only due to craftsmanship issues, but also material limitations.
Its effectiveness was limited to a special attack against Demons, and under normal circumstances, it was just slightly tougher than an ordinary katana.
If Yoriichi had possessed an A-Class weapon, he could have dominated the world back then and been called the strongest.
"Th-Then I'll drink it?"
"Drink up! Once you do, a surprise will happen!"
"Okay~"
'Was it something similar to the pill Kaito-nii had given Brother earlier?'
Thinking this, Nezuko drank the "Demon King Ability Potion" in small sips.
After finishing it, Nezuko didn't feel any different. She expected her body to change, but instead, she just felt increasingly sleepy...
Nezuko began to collapse, losing consciousness.
Kie was startled, but fortunately, Kaito reached out and caught her, holding the small Nezuko in his arms.
"Don't worry, Mrs. Kamado. Your daughter is fine. I've simply given her an ability."
"An ability... Kaito, can you tell me what kind of ability?"
"Well... it's essentially the ability she would have if she became a Demon. But don't worry! The A-Class reward I gave her is the 'Demon King Ability Potion'!"
He explained the "Demon King Ability Potion", detailing its pros and cons. After hearing it, Kamado Kie finally breathed a sigh of relief.
However, hearing that her daughter would become a Demon of sorts still left her with mixed feelings.
The idea of Nezuko becoming a Demon was unimaginable.
Fortunately, unlike being forced into becoming a Demon that needed to kill humans, this seemed more like a genetic alteration.
Mrs. Kamado had seen some cards during the gacha viewing sessions, including ones about vampires and such, which fell into this category.
"This... an A-Class reward, you're really spending too much. I... I don't know how to thank you enough."
With her worries alleviated, Kie's next concern was the embarrassment of Kaito giving her daughter such a significant gift!
This was an A-Class reward!
For the other ladies in the chat group, this was equivalent to gaining superpowers!
Even she herself hadn't received such a high-level reward!
"Haha, truth be told, when I pulled this, I was specifically thinking of your daughter. I have no use for it, and you all will eventually pull abilities you like too."
"B-But..."
"No buts. Nezuko has already drunk it. Can you give it back to me?"
"Well..."
At this point, Kie was speechless. She playfully rolled her eyes at Kaito, sighed, and decided not to say more.
It wasn't a big deal... she could just give Kaito something nice when she pulled something good herself!
'Wait! There were also Hanako and Takeo!'
'Was Kaito going to spend even more!?'
'That wouldn't do.'
'If he gave too much, how would I ever repay him!'
Now Kie was starting to panic. If Kaito gave more, she really wouldn't be able to repay him!
It wasn't like she could repay him by working like a slave for him, or perhaps even offering herself in marriage, right?
But she was past her prime now, how could she possibly do something like that!
"Hanako, and Takeo, although the gifts I have for you two aren't as significant as for your older brother and sister, they are still carefully prepared by me."
"Tanjiro and Nezuko have already caused your mother enough worry. So you two should stay home honestly and run the inn."