[Crossover] The Demon King Wants a Peaceful Life

[Update notice: The author types very slowly and is busy with a day job, but will do their best to update at least three times a week.] My name is Matsudono Tsukihiko, AKA Kibutsuji Muzan, and I'm 1,027 years old. I live in the suburbs of Tokyo, and I'm unmarried. Every day, I pretend to be the head of a distinguished family, take care of the kids, and build a rapport with the strongest sorcerer. I delegate all my work to my subordinates before heading home. I don't smoke, and I only drink in moderation. At night, I send the Twelve Kizuki out to cause trouble and plot with Brain Flower to overthrow the old world. Before bed, I have a glass of special Spider Lily liquor, then spend 20 minutes getting reacquainted with my old friend Sukuna's fingers. I can generally sleep soundly until morning, like a baby. I never carry fatigue or stress over to the next day, and even the Six Eyes says I'm perfectly normal. --The transmigrator Tsukihiko, with his Demon King identity and System, fled the nearly destroyed world of Demon Slayer and slipped into the neighboring Jujutsu Kaisen setting. After several hundred years of smooth sailing, his identity as an illegal visitor was about to be exposed, forcing him into hibernation. To avoid being punished by the native world's will and sleeping forever, he must find a way to earn enough "world recognition" during the plot's busiest period, integrate into the world, and become an indispensable part of it. Time is short and the task is pressing. Other people can't be trusted, so it's more reliable to do it yourself: a little flesh and blood, a large amount of cursed energy, and, of course, the most important part, soul information. These are all essential for creating the Twelve Kizuki! Head of a distinguished family by day, thousand-year-old curse by night. One shares the same ideals as the strongest sorcerer, joining forces to overturn rotten traditions and shatter sinister conspiracies, striving for a better future. The other acts on a whim and is unpredictable, with his Twelve Kizuki stirring up trouble and disrupting the villains' thousand-year plans according to his own preferences. Will anyone notice the deliberately left "loose ends" and catch a glimpse of the truth? Before you read: This is a nontraditional secret-identity story, and no identities are revealed throughout. The male lead is a transmigrated Demon King who's not quite as awful as the original. His Twelve Kizuki secret identities have fabricated backstories with some modifications. The original body controls their lives and consciousness, but to maintain the disguise, he only controls their actions through orders and forcibly taking over their bodies. The secret identities are unaware of this and believe themselves to be independent beings. Theme: Fate is a sleeping slave.