Returning to the Mysterious Era - Chapter 22 - Shadow

When the average man is suddenly thrown into a video game as an extra, fated to die, they might first think to hide or run away. But not Luka. A man now inhabiting the body, he simply wants to survive - no matter the cost - even if it means he has to kill the main character!

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

Year 2035. The virtual reality game, Warlord, changed the world. An Jaehyun was one of the many who wished to change his life through the game. After dedicating his life to the game, he was met with a betrayal. A betrayal by his comrades. As a result, he lost everything. But a chance was given to him. A chance to redo everything again! “I won’t play with others ever again. Whatever the outcome, I’ll show that I can do it alone.” Others rolled a dice to split the spoils of victory. An Jaehyun ate it all by himself. It was the start of An Jaehyun’s solo game life.

In the highly anticipated release of the first-ever VRMMO, Yeager found himself mysteriously traveled back in time. He is poised to rise to the summit and achieve the impossible. Armed with years of gaming experience and a wealth of strategic knowledge from the future, Yeager believes he can bring about the miracle of immortality. But just as the game begins, fate takes an unexpected twist as Yeager finds himself transformed into a young woman. In a tale that challenges identity and defies the limits of virtual reality, join Yeager on a mesmerizing journey of self-discovery as he navigate a world of mysteries, battles, and alliances, all while grappling with his newfound femininity.