Shocking the Jujutsu World with a Sister Complex

My biological sister is Rika, the best sister in the world. She’s perfect in every way—looks, personality—and has always looked after me since I was little. Except for that year when she was ten and got engaged to that boy named Yuta with a ring, which made me feel a little sad and want to cry...

But my sister said I’m still her favorite! She promised to be with me forever, that we wouldn't be separated. So, even after that car accident, and even after she changed, my sister is still by my side (…and my brother-in-law's), and there's nothing wrong with that, right?

Years later, Brother-in-law Yuta was caught one time. After charging into that building alone, I finally understood everything, and the reason my sister became like that. What curse? That wasn’t a curse at all. Why should my sister and brother-in-law be executed just because of this?

Hateful Jujutsu higher-ups, I've noted this grudge. Later, Brother-in-law Yuta was taken to Jujutsu High, and I was forcibly sent by that silver-haired scoundrel to Saitama. That bastard said they arranged a guardian my age for me there, just waiting for us to graduate and come to Jujutsu High together…

And this guy named 5t5 not only can’t be beaten, but he’s really annoying! I've noted this grudge too! I've decided that after I become strong, I'll explore the higher-ups of the Jujutsu world and, while I’m at it, send 5t5 streaking in Shibuya.

***

Upon receiving a call from 5t5, Fushiguro-kun could already picture the triumphant expression on that person's face. Who exactly was he supposed to keep a close eye on? Two days later, the new transfer student appeared on the podium. She smiled, greeting them politely and gently, her gaze seemingly fixed on him.

“I am Itadori Eri. Please take care of me from now on.” She didn't seem to be as much trouble as 5t5 claimed; she looked very well-behaved. Fushiguro Megumi quietly watched her pull out the chair next to him and sit down. She seemed quite quiet and friendly...

Then, the very next day, this quiet and friendly little girl, having just understood what Cursed Techniques and Cursed Tools were, almost single-handedly took down a Grade 2 Cursed Spirit on the third day. Before Fushiguro could even recover, the delinquents in the area were already bowing to her and calling her their boss...

Fushiguro: “…” She’s completely different from how she looks... This girl is absolutely insane!

Tips: CP is Megumi. 1. No breaking up Yuta and Rika, no tormenting Yuta. 2. If compared to black and white factions, the female protagonist's personality is more like a chaotic faction. 3. I haven't finished the manga, so some plot points will be developed based on my own understanding. 4. Some characterdeaths (bento) will be prevented, and the time of the Night Parade of a Hundred Demons will be moved up. Content tags: Comprehensive Anime, Jujutsu Kaisen, Silly/Humorous. Itadori Eri, Fushiguro. A brief summary: In short, Sister Squad! Theme: Live well, for the family you love, and for the self that your family loves.