Owari no Chronicle - Volume 14, Chapter 9: Deciding Factor of the Heart

Xia Zhijun got the title ‘study god’ after scoring first place in the whole city. He’s the model of a good student in a teacher’s eyes: good grades, good manners, and quiet. When he wasn’t smiling, his entire body emits a cold abstinence aura. The girls only have the guts to look from afar and not get close.
Later, it was rumored throughout the entire school that even the study god would fight and hit on girls. Whoever dared to provoke his girl, he would teach you how to be a person at every minute. The night of the graduation ceremony someone saw him blocking Gu Siyi in the corner. He didn’t stop kissing even when she cried. He bit her lips and said in a raspy voice, “I’m going crazy…”
During college finals, Gu Siyi almost bursted out crying, “I’m such a failure. I won’t be able to find a good job in the future…And if I can’t find a good job, I can’t provide for myself…”
Xia Zhijun played with her pink earlobe and remarked, “I’ll take care of you.”
After they graduated, Xia Zhijun created a research company and Gu Siyi became the boss’s wife.
The commercial rocket, “Star of Siyi” was successfully launched. So everyone knew that the new technology superstar, Xia Zhijun has a wife who he spoils a lot.

- Description from Novelupdates

[Decisive killing! Invincible! No Madonna plot! 】

When a thunderbolt tore through the night and a blood moon descended, the world changed from then on, all beasts evolved, vegetation grew wildly, and wisdom was opened.

In just one night, the whole world fell into bloody chaos. The powerless human beings couldn’t stop the mutated beasts and the plants that started the evolution of Ganoderma lucidum, and countless human beings became their meals.

However, the people with the tattoos were horrified to find that the tattoos on their body surface also revived, giving them incomparably powerful power.

Gu Changqing travels back to the eve of the world’s mutation three years after the world’s mutation.

In his previous life, he was reduced to a low-level laborer because he had no tattoos on his body. Now he has traveled back and survived the troubled times. The first thing he did was to invite the world’s top tattoo masters to engrave the world’s top ten demon tattoos: Rahu, Qilin, White Tiger, Black Dragon, Death, Shura, God, Skeleton, Great Sage, Nezha!

Because he knew that engraving tattoos after the changes in the world would not awaken them and become powerful combat forces.

- Description from novelbuddy

I possessed a reliant villain who was in debt and clinging to the heroines.“Why did I give all these good things to others?”From now on, I will solely focus on my own growth.After stopping these villainous acts,the heroines’ reactions were strange.

The strongest Demon Lord dies, and reincarnates as a human. Not only that, he because of various incidents turns into the hero’s best friend.

Follow his journey as he tries to help the hero escape his fate, and on the sideline to conquer the continent while he’s at it.