Abe the Wizard - Chapter 6 - Master's Potion

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

Dr Dalton Wyatt, a world renowned Scientist and Inventor is transmigrated to the body of a high school student Dalton Wyatt who committed suicide due to unfortunate circumstances and complicated life.

An 18-year-old poor college student tried to apply for a job as a tutor but his life almost ended as demons' meal. In his last breath, a mysterious woman gave him a strange power. When he opened his eyes he had turned into a demon with a system that would turn him into… A pervert.

Now he must lived with his dual identity as a model student named Ethan and an incubus named Damian.

Chu He transmigrated into a barren world as a lowly odd-jobber in the Xia clan. He had initially accepted his fate and was ready to spend his life ordinarily and peacefully. Little did he expect himself to suddenly awaken the Checkpoint System which rewarded him for checking into places!

Ding, congratulations to the Host for successful checking-in. For your first check-in, your reward is the Golden Nine Turns. Ding, congratulations to the Host for successful checking-in. For your twenty-one-thousandth check-in, your reward is the Golden Manifestation of Buddha’s Form.

Chu He was certain that the world outside was too dangerous, so he resolved to not leave the book depository until he became truly invincible and peerless, and thus he stayed for a hundred years. A hundred years later, the Tiger clan attacked the Xia clan and planned to massacre countless humans, it was at that moment that Chu He finally showed his hand!