Reborn: Femme Fatale First Daughter - Chapter 144: Li Youmo, the Outrageous Young Sir

At 18, Alex Kain is whisked away to Eryndor, a game-like realm where he gains 'Skill Synthesis', a talent to fuse skills into godlike powers. Battling monsters and conquering dungeons, he builds a harem of strong women drawn to his might and charm. With the power to return to Earth bearing incredible resources, Alex faces a growing threat that endangers both worlds in this epic of adventure, romance, and ambition.

Xin Yun, a sarcastic young man, traveled to an unknown world by chance, but lost his chance to become the strongest because of his obsession with women... or sex. In a collision of the powers of nine powerful men, an incredible thing happened. Xin Yun was reborn back to the time when he traveled to the Isekai world. A fantasy journey is about to begin... [The comic adapted from this novel is popular all over the world]

In novels with a stud there is always a Senior Martial Brother like this:

In the early stages of the novel, his innate talent is high, his cultivation is good, his appearance is handsome, and he has an intelligent, cute younger Martial Sister as a fiancée.

In the middle stages of the novel, he is caught unprepared and defeated by a young disciple (the protagonist) in the sect who’s hardly remarkable at all. From then on, he falls from his godly altar and loses his brilliance. Even his young Martial Sister leaves him for someone else.

In the late stages of the novel, he continues to turn dark, going down the Demonic Path and becoming the major villainous boss. However, the protagonist still ruthlessly defeats him and his soul is eternally sealed.

Once Qin Mo opened his eyes, he discovered that he had become this Senior Martial Brother.

- Description from Novelupdates

Kaius just wanted to unlock his class - instead, he restarted the apocalypse. After years of training, Kaius has barely acquired the first two of his family’s legacy skills. Powerful and vanishingly rare, the method of creating them is a secret people would kill for. Now they might be the only thing that keeps him alive. Narrowly surviving a bandit ambush, he gets trapped in the Great Depths- a world spanning dungeon. To escape, he will have to slay one of the Guardians that defend the exits; a feat no one without a class has survived. Ever. If that wasn’t bad enough, if he succeeds he will reignite a forgotten trial that nearly ended civilization. -Runic-Tattoo Wizard/Spellblade in a world of sorcerers -Exceptional MC, with some initial Slow Burn elements -Large scope, inspired by epics such as Azarinth Healer, BTDEM, PH, and more. -Third Person POV, with a 99% MC focus -Numbers go brrrr -Attack Badger (Friendly?) -Battle maniac MC who is not a murderhobo -No harem, romance, or VR