The Frail Tycoon Has a Secret Identity

Hua Kaiyuan Youli, a frail yin-yang master with narcolepsy, passed out during a battle. To gather the energy needed to return to his original world, he had no choice but to bind himself to a character roleplay System. But when he woke up again, the worlds had merged... A jujutsu high school appeared in Tokyo, five black towers rose from the ground in Yokohama, man-eating demons roamed after nightfall, and a tournament held once every five hundred years began in Japan. The System that had once accompanied him returned, making him don the secret identity of someone who had already faked his death, so he could save this world on the brink of collapse. His best friend from the first world had defected and become a curse user, determined to create a world inhabited only by jujutsu sorcerers. His closest friend in the organization from the second world had defected long ago and joined the detective agency. The Demon King from the third world had been searching for the reincarnation of his nemesis, hoping to turn them into the same kind of being as himself. And in the fourth world, his close friend from a thousand years ago, a great yin-yang master who had reincarnated several times, wanted to create a world inhabited only by spirit mediums... Youli: Why don't you all just fight it out? When he passed by wearing a secret identity caused by the System's corrupted data... The curse user met his best friend again, only to find that the other had become something neither human nor demon. The defector discovered that his old friend had forgotten him and was now standing against him. The Demon King succeeded in turning his nemesis into a demon, only to discover that the other wasn't afraid of sunlight at all and even invited him to sunbathe together. The future Shaman King found the reincarnation of his old friend, but despite being able to read people's hearts, he couldn't understand what was in the other's. Youli: Don't get worked up. I'm still weak as hell. Everyone: Like we'd believe that! Meanwhile, the Hua Kaiyuan clan discovered that their sickly young relative had suddenly grown stronger at an alarming rate. He could take a breath after every step and still easily defeat troublesome demons... After the worlds merged, his constitution remained frail, but his strength had quadrupled. Youli: Wearing my secret identity, I cower and keep my head down. Without it, I hit hard. ★ The protagonist is a powerhouse who keeps his level hidden, beautiful and strong, and loves doing nothing. (Blurb still in progress, but the premise won't change.) ★ There's love-hate tension and play the pig to eat the tiger. ★ No secret identities exposed; pairing undecided. ★ Some OOC is inevitable. Premise: Treating others kindly is treating yourself kindly.