Naruto: Konoha's Kanpu - Chapter 1012: The Truth Uncovered By Yondaime Raikage

Kai of the Sorcerer’s Tower is one of the last mages left, barely surviving in a world ruled by creatures of the dark — where the era of mages ended, and most of the lands got contaminated with dead mana. To save his world and fulfil his master’s last wish, he put himself through a forbidden ritual, risking his soul being ripped into pieces to make his way into the past. In an era with abundant mana — an era yet to enter the Golden Era of Magic. Things go wrong, of course, as they always do, and he finds himself thousands of years before the world fell to mana contamination — in the body of a young lord, Arzan. All is not well, though, as the young lord was murdered by someone right at the cusp of a beast wave threatening the territory, while larger threats loom on the horizon. There was a lot to do for Kai to regain his former strength in this time of primitive technology, but then again, he might just be able to change that.

Yun Che, a big shot in the doomsday, who even the militaries drooled upon, finally died in the hands of his beloved and family. After reincarnation, he wanted to live for his own!

Xing Feng, a rooting third military generation, didn’t lay his heart in the army at all. So when he turned to 20, he chose to leave the army and went into business. When the doomsday came, he accidentally met Yun Chen and started a new chapter of his life, meanwhile, his moral bottom line kept hitting a new low…

- Description from Novelupdates

A little ruffian who fought recklessly without any morals and bottomline accidentally time-traveled to parallel space and became a Key Case Investigation Team agent. The huge change in identity had him creating chaos in the police station. However, a strange miracle system helped him repeatedly solve mysterious cases, turning him into an impudent ruffian detective!

Anger. Pain. Desolation.