(AN: Guess where I got the title idea.)

One year passed.

Katsuo, with Gojo's help, made tremendous progress. Well, Gojo basically gave him books and explained some stuff to him. He even showed his [Limitless] infinity to him, they pressed their hands "together" but he couldn't touch Gojo even after enhancing his body with CE, just like in the anime. It was amazing and that experience gave Katsuo something to strive for.

He also showed his [Cursed Pill Creation] to Gojo and explained its effects, leaving out the fact that it could "take" cursed spirit's innate technique, after all, it's always good to leave some trump cards for yourself. Thinking about that Katsuo couldn't help but be happy and sad at the same time.

Sad because he remembered about the special curse pill he got a year ago. He ate it and unfortunately didn´t get the innate technique [Jagged Claws] and happy because half a year ago he turned a grade one curse into a pill and got this.

[Grade One Pill: 10% chance of getting the innate technique [Inventory Stomach] ]

Its chance was even lower than the special grade pill but he was lucky and got it.

It was pretty gross to use it but very useful. He had to swallow what he wanted to store, so it had restrictions on how wide were the things he could store, and after that, he had to pull or "vomit" them out. Its space was very very big, it seemed that the more cursed energy the user has the bigger the "stomach". Right now he has all the pills he owned, his smartphone, a few changes of clothes, water, and a few nutrition bars stored in his "stomach".

One advantage that it brought in combat was that he could make the pills he wanted appear in his mouth and swallow it, it might seem minor but swallowing a healing pill in the middle of combat can make all the difference.

In terms of CE manipulation, he can now amplify his Innate Technique and negative energy.

(AN: I think that amplifying negative energy means increasing the purity of cursed energy, at least that was what I understood after reading and re-reading about Satoru Gojo techniques in fandom)

When he did that, he could feel the restrictions on his technique loosening a bit. He could turn a grade two curse into a pill with just one touch and the same would happen to grade one's if he touched it with two hands and let it struggle a bit, of course, there were exceptions. If the curse's technique was very destructive, it could break free from Katsuo's [Cursed Pill Creation] which required him to beat it around a little more and try his innate technique on it again.

He called the technique [Pill Creation: Forced Refinement].

Gojo let him try it on his [Infinity] and commented that he felt a strange force of attraction on his cursed energy and that if he wasn't at least a little bit focused it could maybe destabilize his [Infinity].

Basically, he said it was impossible to affect him, but in nicer words. Well, not working on Gojo didn't mean it wouldn't work on other sorcerers so he didn't mind much, he finally had a kind of offensive skill.

Remembering Gojo's words he had an idea. He used [Pill Creation: Forced Refinement] on his own cursed energy, he felt a bit weird doing it, like his cursed energy was sucking and transforming itself and this was the product after using 5% of his CE.

[Grade One Pill: Mass of cursed energy. Unable to be consumed]

He became confused and researched the pill, it didn't respond to any of his probes but he, of course, didn't consume it. He trusted his technique enough to heed its warning. When he tried to apply force on it, after applying enough strength to crush a bone, the pill was flattened and an enormous amount of cursed energy was dispersed through the atmosphere, which attracted a lot of curses that he promptly turned into pills. He got a few hundred.

While he didn't have the means to fully research it right now, he had found a good use for it so he put it aside for now.

Recently, Gojo also taught him the way of creating positive energy, the reversed cursed technique, he even bragged he once healed himself after his throat was cut through and his head was pierced, but he still couldn't heal others, something that few in a thousand years accomplished, according to the books.

In Katsuo's mind, being able to heal himself from fatal injuries like Gojo said he did was already a form of immortality. He desired that kind of ability so he started devoting some of his time to learn the reversed cursed technique.

He was training it in his room when he sensed an abrupt spike and instability in his sister's cursed energy downstairs.

Yua POV

(AN: It's hard to do this in the first person because children are not very aware and if I do, she will not feel like a child, so I will do it in the third person)

Yua was excitedly and impatiently pacing in front of the living room flat television when the show she was waiting for started.

"It's starting, it's starting, Puri Puri Princess!!"

The anime intro started playing and Yua was cutely dancing and singing alongside.

"With the power of love and friendship~"

"Puri Puri and company will win against all evil~"

"No bad guys will stand on their way~"

"To save the world from Puri Puri's sister's schemmes~"

...

"Aku Aku Princess will never win~~"

(AN: Aku means evil)

As it finished, Yua sat, flushed, huffing and puffing, on the sofa and attentively watched.

In the beginning, everything was going alright Puri Puri saved her friend and was Yua very happy.

"Puri Puri never loses after all."

But it was a trap made by Aku Aku Princess and Puri Puri was in a pinch.

"That's alright, Puri Puri will find a way."

No hope was in sight and Yua was in tears, sad for the princess and angry at Aku Aku.

"Don't lose, Puri Puri Princess, fight!! Use Friendship Beam!!"

As time passed and Puri Puri continued to struggle and Yua started feeling stifled like something was struggling to get out, so she punched her fist in frustration and something did get out of her body.

Yua POV ended

Katsuo, as soon as he felt Yua's plight rushed out of his room as fast as possible, using the walls and even the ceiling as a foothold to reach there at the highest speed possible and under a second later he was next to Yua, watching as she punched and a black bone exoskeleton with purple muscle fibers filling the gaps formed around her fist and continued forming until the elbow, of course, this process was extremely but Katsuo saw it as if it was in slow motion due to his enhanced senses.

After that Yua turned pale and stumbled backward but Katsuo caught her while continuing to look at his sister's arm.

'It can't be, can it?'

He looked at his sister that started crying desperately.

"Kat-nwy-chan! Is Yua going to die?!"

He embraced his sister tightly while calming her down.

"Of course not, how silly Yua is, you only need to listen nii-chan and everything will be alright"

Yua nodded while sobbing.

"First, I need you to take big breaths and stop crying, if you do, nii-chan will give you sweets later"

Thinking of sweets, she started taking big breaths and began to calm down.

"Okay now you have to think about your ugly arm going away"

Yua made a focused face and strongly thought about it and her black and purple arm started melting away.

After that, Katsuo used [Inventory Stomach] and spitted a CE recovery pill in his hand which he fed to her.

Yua started looking better and Puri Puri voice was heard.

"Friendship Ultra Beam! Aku, you will never win!!"

"Yes!! Puri Puri won!!"

Katsuo looked speechlessly at his sister and at the television, managing to understand what happened earlier.

He took a breath and said to his sister.

"I need you to do nii-chan a favor and close your eyes?"

"Why?"

"It's to find out what happened to you earlier, just trust nii-chan!"

Yua nodded and shut her eyes.

"Now ask yourself, what was that black and purple thing."

She was silent for a moment before saying.

"Curse Armor. What's that?"

'Indeed, I was right.'

"It's your superpower"

Yua made a surprised Pikachu face.

"But it's so ugly!!"

Katsuo looked speechlessly at his sister, according to the books, a lot of people would kill to have an Innate Technique like hers' and thinking about that made him worry about her getting too involved in the jujutsu world. He concluded that he will keep her away from it until she reaches maturity and can choose for herself. Until then he will help her grow so that whatever choice she makes, she doesn't regret it.

"No worries I'm going to help you make it beautiful."

Yua hugged her brother happily before freezing as if remembering something.

"Kat-nii-chan, where are the sweets you promised!!"

Katsuo also froze as he remembered he didn't have any.

"Do you think nii-chan was lying to you?! I will give them after dinner."

'It seems that I have to do a quick visit to the convenience store.'

Katsuo thought with a chuckle.