Tower: Rebirth of the Absolute Demon - Chapter 1: Ch : Betrayal on a Night of Roses

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.

After Reincarnating into Naruto World at the Warring State Era as an Uzumaki, Masahiko thought that he got a useless System. He lived for 48 years as a normal, below average Uzumaki Shinobi.

That changed when he finally knew how the system works the day of his 49th Birthday!

- Description from Novelupdates

By coincidence, Li Yunmu found a super machine from humanity’s age of darkness. From that point onwards, his ordinary life would never be the same! Aptitude? Innate talent? What are these? Could they be eaten?

I have neither aptitude nor innate skill, but my shadow can level up using hacks. Experience, Ability points, battle prowess… all of them could be hacked. Even while he is asleep or tired, he could still increase his skills.

- Description from Novelupdates