Transmigrated Become Sukuna, but the host is Yukinoshita Yukino?

I traveled through worlds again. 

No, to be precise, this doesn't really count as traveling. 

I just lent my system—something that wasn't all that useful to me—to Yukinoshita Yukino so she could experience a "cheat mode" life. After that, to avoid the world's will from wiping me out as some kind of "outside demon," I made a strategic retreat. 

In simpler terms, I exploited a bug to make the world believe that I *am* Yukinoshita Yukino, rather than some multidimensional invader.

This decision was also agreed upon with the system. 

For Hayashizaki, it was like a bear hibernating—he could just sleep quietly in the soul realm. If he ever got bored, he could pop out and tease little Yukino for fun. 

In fact, he had already woken up from a nap, so now he wanted to see what young Yukino was up to. 

Hayashizaki opened his eyes in the soul realm. 

… 

"Mr. Yamamura, it's been a long time." 

Yukinoshita's father was dressed in a crisp white suit, smiling as he shook hands with a middle-aged man in his fifties, who was also in formal attire. 

"Mr. Yukinoshita, it's been a while. I hope you've been well." 

Yamamura smiled as well. The two of them looked like old friends happily reuniting, but their conversation had a strong business tone. 

It wasn't that they had a bad relationship. Both Yukinoshita's father and Mr. Yamamura were prefectural assembly members, and they had a decent personal connection. But in high-society gatherings like this, formal greetings were unavoidable. 

"Mrs. Yukinoshita, I hope you're doing well too." 

After greeting Yukinoshita's father, Assemblyman Yamamura turned to the mature woman beside him, who was wearing a kimono and had her hair neatly styled. 

It was well known that women in Japan didn't have high social status, but Yamamura didn't underestimate this elegant and dignified woman in front of him. 

There was a reason why Mr. Yukinoshita had married into her family. 

"Hello, Mr. Yamamura." Mrs. Yukinoshita gave a slight bow, then gently patted the back of the short-haired girl beside her. "Alright, Haruno, greet Mr. Yamamura properly." 

Yukinoshita Haruno's lips curved into a graceful smile. She mimicked her mother's bow. "Hello, Mr. Yamamura." 

"What a beautiful and intelligent young lady," Assemblyman Yamamura praised. 

"Not at all, she still has a long way to go." Mrs. Yukinoshita covered her mouth with a soft smile, every move exuding the elegance and grace of a refined Japanese woman. 

After greeting Yamamura, Mrs. Yukinoshita led Haruno around the banquet, exchanging pleasantries with the influential figures attending. 

It wasn't until Haruno used the excuse of needing the restroom that she finally got a break. 

"Phew… That was exhausting." 

She splashed cold water on her face at the sink, trying to clear her foggy mind. 

The banquet was full of different kinds of people, but they all had one thing in common—the masks of smiles they wore. Behind every cheerful toast and polite chat, alliances of interest were being silently formed. 

To fit in, she had to put on a mask too, but it made it hard for her to breathe. 

Looking at her reflection in the mirror, Haruno stretched her lips into a forced smile with her fingers. But her eyes remained emotionless, making the expression feel eerie and unnatural. 

She stared at her fake smile for a moment before finally letting her face relax, sighing softly. 

"Sigh… I really envy little Yukino. I wish I could go abroad too. I can't stand being in this house anymore!"

She let out a small huff, almost like she was pouting, but even her attempt to act upset felt a little fake. 

It was obvious—she was just venting, saying meaningless things to let off steam. After all, she had chosen this path herself. 

She had stepped forward so that her beloved little sister wouldn't have to carry the same family burden she did, wouldn't have to be shackled by such heavy chains. 

As long as it was for Yukino, it was all worth it. 

Besides, it wasn't so bad, was it? 

She was talented at playing along, at putting on a front, and she did it well. 

She had met every single one of her mother's expectations perfectly. 

In her parents' eyes, she was on the right track to becoming the ideal successor. 

Yukinoshita Haruno kept repeating that to herself, trying to calm the restless thoughts in her mind. 

… 

I give up. 

I just praised you, and now you pull this on me, system? 

Lost again, huh? 

Where's Yukino? 

Inside the soul domain, a black-haired young man watching everything through Haruno's eyes rubbed his face in frustration. 

"So Haruno was already starting to turn into a masked rider at this age, huh? Growing up in this kind of environment, no wonder she became like that in the future." 

Hayashizaki murmured, deep in thought. 

"She's still so young… Looks like she's just in middle school." 

He could still see it in Haruno's expression—the struggle, the longing for freedom, the envy toward her little sister. 

She hadn't completely accepted her fate yet, not like she would in the future. 

Wait a second… 

A realization suddenly hit Hayashizaki. 

His original plan was simple: he would exist inside Yukinoshita Yukino's body. Over time, she would naturally gain cursed energy due to his presence. Since his soul wasn't bound to the system, he wouldn't be affected by its underlying logic. 

The cursed energy accumulated during her childhood would be there when he returned to his own world in the future. By retrieving the part of his soul temporarily placed in her, he would receive a feedback boost. 

A perfect win-win situation. 

But now… 

It shouldn't be happening this fast, right? 

Hayashizaki felt a little uneasy. 

Then he saw it—Yukinoshita Haruno standing in front of the mirror, her figure flickering for a brief moment, like a shadow slipping through reality. 

She didn't seem to notice anything unusual, but Hayashizaki caught it right away. 

"You've gotta be kidding me…" His eyes widened in shock. 

Sure, most sorcerers usually started sensing their cursed techniques around seven or eight years old. 

But this… This was way too fast! 

How long had he even been awake? 

Even with the system's subtle enhancements, it still took two days for Yukinoshita Yukino's body to awaken its cursed energy. 

And yet here she was? 

"Haruno always had to be better than me at everything. Everyone liked her more too." 

Hayashizaki suddenly remembered Yukinoshita Yukino's words about her sister.

Looks like Yukinoshita Haruno can no longer continue the life she once had. 

"Girl, do you want to know the meaning of life?" 

"Do you want to truly live?" 

In the luxurious hotel bathroom, the shackles binding the wings behind Yukinoshita Haruno suddenly shattered. 

… 

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