Valerian, The Legendary - Chapter 304 - Daily Life Of An acolyte.

Xin Yun, a sarcastic young man, traveled to an unknown world by chance, but lost his chance to become the strongest because of his obsession with women... or sex. In a collision of the powers of nine powerful men, an incredible thing happened. Xin Yun was reborn back to the time when he traveled to the Isekai world. A fantasy journey is about to begin... [The comic adapted from this novel is popular all over the world]

Everyone knew Shen Nianshen so well.
In this world, there would probably be no female creatures that could enter his heart. Even the most beautiful girl in the school was coldly rejected.

Until one day, when there was a basketball match at the school. In the front row of the audience, there was a girl whose head was accidentally hit by the ball.

Shen Nianshen immediately ran to her. Everybody thought that he only went to get the ball. Unexpectedly, he squatted down in front of the girl, stroked her head gently, and asked anxiously, “Does it hurt?”

This a sweet love story between a cold guy and a lively girl.

- Description from Novelupdates

There lived an extremely miserable man- he suffered from a terminal illness. But one fine day, when he left his miserable body, a certain entity grants him another chance- another life along with few gifts to help him in his journey.The man is transmigrated into the body of a young man into an ancient society. Watch how the man lives his new life and conquers the world.[This book will contain R18 scenes but do not expect it to be the theme of the book. It will be mostly based on strategies and expansion of empire. A small advancement in the technology can also be expected.]

The story is about a a hitman, Who dies because of his own recklessness and transmigrates into a game he used to play after his retirement as a hitman.I'm not gonna spoil any further, but i might answer few of your questions.Is MC overpowered?Nope, he'll become strong over time and all battle he'll fight will be because of his effort and techniques.Is there magic and adventure?Yes! It have both magic like normal isekai with adventure and fighting with monsters and many other things. There are other important things like “Essence Stone” But let's talk about it in the chapters.There will be harem?Not really, He will be in contact with many beautiful female and males but one waifu but i haven't decided yet.All i can say is, give it a try, I'll try my best to make it worth your time.