Otaku Witch - Chapter 943 - 582. Watch carefully, this is how Hat Senior Sister is used.

The notorious imperial court lackey and the meritorious military general were well-known for their mutual dislike, a pair of arch-enemies set in stone. Who could have foreseen the unexpected change in the winds of heaven: the general injured on the battlefield, both legs disabled, and even forced by the emperor to marry his nemesis.  

With one marriage edict, two people with mutual hostility are forced to marry and live under the same roof. Yet after these long days together, they come to the realization that this fellow is not truly devoid of any saving grace/unattainable and high out of reach.

- Description from Novelupdates

A phoenix is a creature of legends, a wonder of the world, an imagery of life and destruction. This fabled creature signifies the rise of a hero in a virtual world where battles occur for the sake of honor and glory!

Ye Zhen, a female Ph.D. in the Department of Mathematics of Huada University, changed her career to enter the entertainment industry in order to investigate the death of her birth father, Film Emperor Ye Yi. During her interview, she accidentally made CEO Rong Cheng Jue lose face in public. Yet Rong Cheng Jue, unlike what was to be expected, didn’t take old grudges into account and let Ye Zhen join his company. When everyone thought Ye Zhen would become Rong Cheng Jue’s personal secretary, she actually joined the entertainment department. After several twists and turns, Ye Zhen became an errand reporter for Rongcheng Entertainment’s “Treasures of Great Tang”.

Her colleagues’ bullying towards her, the pressure of changing career, and the many obstacles in her investigation all left her confused. Under Rong Cheng Jue’s silent guardianship, she didn’t forget her original purpose, overcame every obstacle, and eventually became an ace producer.

Ye Zhen and Rong Cheng Jue shared a common belief : no matter how bleak the hope is, how thorny and dark is the road ahead, they had only one thought in their hearts: to uncover the truth, and therefore bring peace to the soul of the Film Emperor Ye Yi.

- Description from Novelupdates

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.