Himekishi ga Classmate Isekai Cheat de Dorei ka Harem - Chapter 3Vol 1

Ajax was an orphan who survives a massacre along with his friends but unfortunately gets separated from them.

Fortunately, after a turn of events, he successfully gains a system which helps him increase his cultivation, but doesn't know what it is called.

But he knows one thing for sure, this system is very powerful and helpful in taking his revenge.

“Whoever you are, I am gonna find you”, Ajax mumbled himself with a disgruntled expression.

In a world where Summoning of an elemental spirit is done through a dream when they are 15 years old, Ajax with the help of a system and his summoned spirits sets out on a journey to seek revenge against the mastermind behind the massacre.

Growing up parentless, Shi Yan, who was left with a large amount of inheritance money, bore a general disinterest in life.

The only times he felt alive was when adrenaline coursed thorough his veins. He quickly found that extreme sports, bungyjumping, cave diving & skydiving, gave him the biggest kicks. The bigger the adrenaline kick, the closer he was to death, the more alive he felt.

Waking up in a pile of dead bodies in an unknown land, after a diving adventure had ended disastrously, he quickly realizes the body he now possessed was not his own.

Follow Shi Yan as he explores this new world where danger lurks around every corner, and death is only a breath away; a world in which Shi Yan could not feel any more alive.

Crossing to One Piece world, he became Roger’s younger brother.

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