10 nen goshi no HikiNiito o Yamete Gaishutsushitara Jitaku goto Isekai ni Ten'ishiteta - Chapter 10, Pioneer Leader/Defense Captain Yuuji Is Doing the Job of a Pioneer Group Leader Prologue

This is a story about Gong Lixin who was the young master of an ancient underground palace in the ancient times. He was raised by his master and forced to partake sexual relationships with numerous people to cultivate his Yin Body. His master who has a Yang Body was going to absorb him after he has reach a level to become stronger. MC refused and killed his master also dying at the same time. Then he transmigrated to the modern time and thinking he will enjoy peaceful life, the end of the world arrived.

Being someone with no special powers except for his martial arts, see how he use his martial arts to dominate the times and find his lovers.

- Description from Novelupdates

Probably Shy Loyal Dog Gong X Slightly Blackbelly Used Goods Shou

When a new neighbor moves in across from Chen Xiao, he sets his sights on the handsome young man, Gu MengYang. Though he’s coming off a bad breakup, he still wants to find love with a new man and wants to bully that man along the way!

Meanwhile, his fellow blackbelly friend from childhood, Luo Xin, noses in to “help” him catch his man. And, behind the scenes, tries to find a love of his own.

In the eyes of outsiders, Hyuga Yuuto is a genius in the traditional sense of the Hyuga family:

Tough, strong, gentle, and calm, he is a partner worth relying on at all times.

However, no one knows, in countless silent nights.

The young genius of the separation family stroked the caged bird engraved on his head and fell asleep with the sharp needle in his mouth, fearing that in his sleep he would reveal the madness and anger deep in his heart——

“What Uchiha Itachi can do, I, Hinata Yuuto, can’t dare to do?”

- Description from novelbuddy

On the will left behind by the 14 year old suicide victim K:

“Taku Sugawara is the devil. Nobody should believe his words.”