The Zoldycks Are All Big Sisters' Boys

Kabu is a retired transmigrator.

Lately, she's had a bit of a problem. You see, every transmigrator gets a random identity after retirement.

And she...

In this world, she became the rebellious eldest sister of a family of assassins. In her reckless youth, she injured her great-grandfather, grandfather, the family head, and her younger brother, then ran away from home for years.

Kabu: I know it's all fake, so why do I still feel guilty?

But no matter. It's just an identity, and she probably won't have anything to do with them again.

Then...

Killua: "Big Sis, please take me in!"

Alluka: "Big Sis... please."

--Why does this identity come with so many little brothers?!

Kalluto: "Hmph. They can stay, but I can't?"

--This one is even more alarming. He looks seriously unwell!

Illumi: "Big Sis, long time no see. Please hand them over to me."

Kabu: "...What a deal. Take them away, quick!"

Illumi: #Delighted##Of course Big Sis loves me best##Happy#

--Something feels off. Why has his gaze suddenly gotten so strange?

Theme: The protagonist is ten thousand years old