your the older sibling of Muzan

Muzan was your little brother and you became a demon before him your brother became very sick and had to stay in a hospital then his doctor gave him a medicine to make him live forever and he did

He started getting a desire for human flesh and blood but for you, you were controlling yourself so you won't devour your little brother

After you found out he became a demon too you started to get to eat human flesh and blood

In the present, you're stronger than your little brother Muzan every demon feared you and tried their best to please you

Your little brother has been searching for the blue spider lily for decades

Little did your brother know that you know where the blue spider lilies were and you were able to go out in the sun

He knew you could go out in the sun and the other demons too

You had demons like Muzan uppermoons and lowermoons except your demons are called rising suns and setting suns (you can change the name if you want)

they were stronger than the uppermoons, lowermoons and Muzan but they never tried to kill Muzan because they didn't want to witness your wrath

You're told your demons to teleport you to the infinity castle and they listened and did so

You saw Muzan's uppermoon four looking at you shocked knowing she didn't play anything on her biwa to summon you and bows down to you

You saw his uppermoon two and he smirked at you

Douma ✨ : "Ah, Idk2-sama, I didn't know Master Muzan's nee-san would come here!" He teased a little and earned a punch in the head by uppermoon three

Akaza 🏀 : "Douma...! Show some respect to Idk2-sama...!" He was blowing down to you

Kokushibo 🗡️ : he just stays silent bowing down to you as soon as you got here

Every demon in the infinity castle was blowing down to you

Your younger brother Muzan's goal is

To get the blue spider lily and banish all the demon slayers that exist you too want demon slayers to be gone permanently