Itai no wa Iya nanode Bōgyo-Ryoku ni Kyokufuri Shitai to Omoimasu - Chapter 440

After breaking up with his girlfriend, he accidentally acquired a genius system and rose from there against the heavens, becoming invincible..

- Description from Novelupdates

Just as a gamer found an overpowered skill book called ‘Item Upgrade’ in the hottest virtual reality role-playing game on Earth, something happened to the game’s system, causing his soul to leave his body and go to another dimension. Common sense dictates that he would be born anew then become the greatest overlord of this world by making use of his advanced knowledge. Not in this case! He was already dead. Only some fragments of his soul and that skill book managed to get into that dimension and merge with an ordinary common youngster called Bai Yunfei.

This was the enormous Tianhun continent, where humans could be said to have no limits. There was a group of humans here who could cultivate the power of their own souls then control their bodies, the natural elements and even other people’s souls with that power! These special beings were called — soul cultivators. Come witness how the several fragments of the dead inter-dimensional traveler’s soul and that skill book, which was not governed by the laws of this plane, were going to help Bai Yunfei become a legendary soul cultivator and craftsman!

“Hey, have you ever heard of the lunatic roaming around the tower?”“Are you kidding me? Who haven't heard of him yet!?”“Hey hey, are you talking about... that person?”Interesting news travels even faster than light, especially regarding the mysterious figure that everyone in the Ethereal Tower is curious about, the lunatic ascender whom thoughts and deeds are so off-place that even the greatest among them just couldn't grasp his intent, almost as if he is ascending a completely different tower than them.While everyone in the tower talks about the lunatic who lurks on each tower's floor more than he is supposed to, the person they are talking about just goes on his merry way to collecting treasures he wants, and while the world is talking about him.“Come on, give me some luck, maybe roll the hundred times multiplier again...”He's sitting while rubbing his palm together, gambling on something that will make everyone faint.

A fighting genius.