Sage Monarch (Sage Emperor) - Chapter 1593: Increased Prestige

After dying in an oddly anticlimactic vending machine accident, Kazuki Ren is reincarnated in the demon realm—not as a hero, not as a villain, but as the only human male student enrolled at the mysterious Academy of Ruin, a school where all the professors are demon lords and all the students are powerful, beautiful she-demons.Ren is told he has one task: survive.But there’s a catch. The Academy’s darkest secret is about to awaken, and Ren holds a hidden power that could either destroy the demon world... or rule it.Now surrounded by seductive demons with hidden motives, eldritch tomes, forbidden dungeons, and twisted exams, Ren must master his ability—or be consumed.Magic, mystery, danger, and temptation await in this dark academia harem fantasy.

As the leader of bandits, Yan Jinyi has been a bully for twenty years, and she ended up causing her own death. The next thing she knows, she wakes up and finds that she has become the Second Young Mistress of the Huo Family. Wielding her knife, Yan Jinyi starts to throw her weight around conceitedly again. Young Master Huo says, “If I’m still single, I’ll probably marry my sister-in-law.” Third Young Master Huo says, “If I could turn back time, I would have vied with my brother to marry my second sister-in-law. Miss Huo says, “If I were a man, my second sister-in-law would be my woman!” A CEO says, “I thought I was roguish enough, but I didn’t expect Yan Jinyi to be more of a hooligan than I am!” The Best Actor says, “Huo Xishen, why are you still not divorced?” Second Young Master Huo points to Yan Jinyi and says, “She is mine.” Rumor has it that the second daughter-in-law of the Huo Family can beat a home wrecker up and is especially good at making money. Countless bigwigs are lining up to make a cuckold of Huo Xishen.

When he wakes up, Su Changkong has traveled to a world where troops are chaotic and demons are rampant, and his martial arts qualifications are mediocre, but Su Changkong found that as long as his [lifespan] increases, his talent and potential can be [infinitely] improved!

Wu Qin Xi: imitating tigers, deer, bears, apes, birds and other animals.

Turtle Breath True Dinggong: Imitation Qigong, like a thousand-year-old tortoise breathing, breathing, breathing and closing for a long time, prolonging life!

Celestial silkworm magic: nine transformations of the silkworm, breaking the cocoon into a butterfly, rejuvenating the old and rejuvenating, opening the door of life and death, every transformation is a rebirth!

Cultivation of health boxing, practice the Qi of longevity! There are many corpses on the road of longevity, and Su Changkong has embarked on a longevity martial arts where heaven and earth are destroyed but I am immortal!

- Description from novelbuddy

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

- Description from Novelupdates