Mr Gu's First Doting Marriage - Chapter 109 - 110: She is Driven by Jealousy

Lin SuCi transmigrated into a book, and became a kitten who had just cultivated into becoming human.

When he was still young, he was picked up by a good man to be become his apprentice, but he did not expect his master to let his senior — the number one villain in the book — raise him?

This villain senior was too scary, when he had nothing to do he would put him on a plate and stare at him. Let’s not mention cuddling, embracing, stroking and pinching him all day long, he even had a hundred ways to bite a cat!

Lin SuCi covered his butt and had a tearful epiphany, Senior wants to eat me up!

Having tried to run away with his short legs and getting caught for the nth time, Lin SuCi, his paws covering his face, had to accept his fate.

Wasn’t it to just be the boss villain’s favored younger brother? Take your hand off my tail, fine, I’ll take on this role!

- Description from Novelupdates

Vahn was an atypical youth. Due to a rare mutation, his blood had the potential to target and attack ailments within the human body. Touted as a universal cure, people had elevated his status above the norm and given him the classification "Panacea". In the media, he was hailed as a great hero who would usher in a new era or human wellness. However, behind the scenes things weren't so bright. Being a unique individual, Vahn spent his entire youth locked up in a lab with various scientists and research teams using his body and blood to perform endless amounts of experiments. The only solace in his suffering was the various anime and manga made available to him between experiments. He often imagined himself as the protagonist in a world of his own, finally in control of his own destiny. For years he nurtured this desire, until at the age of 14 he died when an organization had tried to kidnap him from the lab...

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

A fluffy, sweet modern GL story about a mature older women and a cute university student.