Cultivation Through Artifacts - Chapter 4: The Diary

Based on the popular Vocaloid series, by HoneyWorks, called “Kokuhoku Yokou Renshuu (Confession Rehearsal)“:

Natsuki, a third-year at Sakuragaoka High School, who holds unrequited feelings for her childhood friend, Yuu, who’s in the Film Club. However, instead of being honest about her feelings, she makes him be her confession “rehearsal” partner. Unable to say her true feelings, things start to get complicated when Miou and Akari, who are also in the Art Club, get involved! Will she ever be able to confess for real!?

I was reincarnated into another world, and I’ve brought the Horadric Cube from Diablo II with me.
Being a knight is cool and all, but being a wizard is pretty neat as well.
So, which one will it be?

- Description from Novelupdates

[Warning: Mature Content and a ruthless, villainous, badass mc!]Kael Draven was once the feared leader of an underground mafia empire. A shadow ruler who pulled the strings behind the scenes.But power comes at a price. Kael learned that the hard way when a bullet pierced his ear, and his trusted ally betrayed him, bringing his life to an end.Bang!As his empire crumbled and his body hit the cold floor, all he could think was, ‘What a pathetic way to go.’Instead of hell, Kael woke up in a far more dangerous world, with a body stronger than ever—youthful, shredded, with muscles for days and an ego that could crush mountains.His title? Master of the Crimson Maw.He now led a bandit group that had angered a mysterious force and been wiped out—except for one survivor: a strong, silent gladiatrix who wanted nothing to do with him.To make things even more interesting, his body bore a glowing tattoo that whispered in his mind: “Bond. Through body. Through soul.”But Kael wasn’t one to back down. He didn’t like losing.So what if his base was a dilapidated shack? So what if his army was just one extremely voluptuous warrior?Kael wasn’t here to play small. He was going to turn this ragtag bandit group into a force feared by all, with a harem of deadly beauties who would bow to no one but him!Welcome to the Crimson Maw. Where the training is brutal, the beauties are overpowered, and the only thing more dangerous than an enemy is the bandit king himself.Let the grind begin!

A fighting genius.