Jujitsu Kaisen x SukunaSibling!Child!reader

Your first Mission

"Principal Yagi, I know what they are." Gojo said as he walked with the stoic man beside him. Yagi grunted, encouraging him to continue.
"They're the younger sibling of Sukuna, wondering how I know?" The male asked enthusiastically. Yogi turned to him as he opened a door.
"Sibling? There's no record of Sukuna ever having a sibling. They might be a phony." Yagi said as the two walked in the hall. You were on the way to the bathroom because you wanted to explore. You overheard the conversation and hid behind a wall.
"The kid literally melted into Yuji and didn't die because of sukuna. He was actually calm. I think they should stay away from each oth- " He didn't get to finish because you had summoned an extension of your arm to hold both of them by the throats. Gojo couldn't activate his technique, so he was choking alongside Principal Yagi. You looked at them dead in the eyes and said,
"Dare to keep me from my brother, and I'll slay this whole building in a snap of my fingers. Do you want control of Sukuna? Let me and him be together." The two males nod as they struggle to breathe. You linger for a second before letting go and turning away. You disappeared before they looked up. They looked at each other before nodding in agreement to leave you alone. Doesn't mean they won't keep an eye on you and Sukuna.

Your first mission happened abruptly. By abruptly, I mean you were taken without consideration if you wanted to go.
It was rumored that there was a finger holder around an abandoned building, feeding on people. You were able to hide your excitement inside but acted like you didn't want to go. Megumi was holding you as him, and Yuji walked.
"There should be a curse around here somewhere. Maybe tiny here could slay it better than you can." Megumi said nonchalantly, earning a whine from Yuji. You giggle silently at the interaction before you hear a noise, and so did the two of them. You ask to be let down, but Megumi held on tight.
A curse sprung beneath your feet, knocking them both down. You were unscathed and annoyed that your clothes were dirty. The boys looked up to see your annoying face. You were hungry, so you got yourself some food. Easy peasy. The curse didn't have time to react or fight as you started twisting its limbs, slowly and painfully, to a curse. The insides of the curse slowly turned outwards, making the curse barely let out a sound. The boys, frozen in place on the ground, watched as you turned the curse, basically, insides out. Once you deemed it dead, you made sure it didn't disappear before you ate it by letting out your demon aura, specifically around the curse. Demon aura counteracts curse energy by making it stay in place. It's more powerful than curse energy. You emit as you walked towards your meal, it cowering to a kneel before you. You put your hand on its head before easily snapping it off as if it were paper. You took a bite as you tasted the energy, filling you up, the blood as an extra drink, you eat the curse entirely. With finishing the foot, you look back at the boys, expressions so shocked, they never said a word. Sukuna, who was watching the whole thing, cheered loudly in Yuji's body. That effectively brought Yuji out of the daze he was in.
"What the fuck just happened?" He stood in shock. Megumi is still on the ground, answering.
"They ate it. They ate the curse....like....raw.....and alive." He said quietly, debating on telling Gojo. As if on cue, the said male suddenly showed up. He took a quick look around before he spotted Megumi on the ground, unmoving.
"Oi, oi, what happened here? Did you kill the curse?" Gojo asked with a curious smile.
"No."
"No." Both boys said simultaneously. Gojo lowered his smile and was now fully interested.
"Well, where is it? If it was that hard to kill, maybe -"
"We didn't kill it because the kid ate it." Megumi said, still in a daze. Gojo flicked his head towards him with a stunned look. What did you do?
You look up from your bloody hands, wipe your face with your sleeve, and catch sight of Gojo standing there. You shoot a sweet smile at him before going back to cleaning your face. It had gotten all over your mouth, and you were wiping with the sleeve of your kimono supplied by the school. Gojo stammers, not knowing what to say. You had finished wiping and wanted to be held. Yuji and Gojo silently debated which one to hold the curse eating child. Yuji sighed and picked you up.
At that moment, Sukuna popped out on his cheek and praised you.
"Look at that massacre, blossom! Im so proud of you!" He cheered, you giggled and nuzzled against the face before it disappeared again. You then yawned, exhausted from exerting energy, and promptly fell asleep on Yuji's shoulder. Yuji just looked traumatized at Gojo before following him to the car.
Megumi and Yuji look blankly ahead as they walked, you were fast asleep and cozy.

Once they got back, nobara noticed their gloomy expressions and asked what was wrong.
"Oi, what's up with you boys? You look like you've seen something you've shouldn't!" She said as if she got something they didn't and was bragging. Megumi answered with no emotion.
"The kid ate the curse we were supposed to kill." Nobara blinked, then laughed at them.
"There's no way this child ate a curse! It's impossible! Hahahahahaaaaa!!" Yuji then walked in with Gojo, putting you on the couch. Nobara's laugh simmered down to a giggle but stopped once she noticed the black blood on your kimono. It still reeked of curse energy but was dwindling down.
"Oh my God, they ate a curse." Nobara finally accepted the fact and covered her mouth in shock. The boys nodded, and finally, she understood the shock. You hopped down to change and went to go get another kimono. All 3 first year students immediately talked about it like you weren't there.
"So what technique did they do? Was it cursed? What was it? What did it look like?" Nobara rapidly fired questions at the two boys. They did their best to answer as honest as possible, keeping the fact that you didn't use any cursed energy.
You were changing in a private room, looking in the mirror.
'When will we be together again, onii-chan?' You thought. You change into a white kimono, like you saw your brother wear while in Yuji's mind. You let out a tiny 'humph' before walking to the living room. You wanted chocolate cake now.
"Want cake now, please." You say as you saw the teens huddled together. They turned to look down to you and complied immediately.
You got a cake in less than 20 minutes and ate a piece before giving the rest to them.
You wanted to go to bed, so you said night and went to Yuji's room. The teens saw you head to the pink haired males room, but didn't try to stop you. You liked this feared princess treatment you had with the people here, what are they gonna do? Kill you? You're already technically dead. You laugh as you hold a pillow like a stuffie, and promptly dream of you and your brother.

Sorry this took so long to get out, it's been hell for me lately
U will be getting another chapter soon, hopefully