Transmigrate inside a Web Novel as a Side Character. - Chapter 196 - Trapped.

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.

Lu Chengye’s dream was to live freely and have fun until he died. Unfortunately, he inherited a company and was worked to the bone!

After finally taking over the company, he had just prepared to begin his carefree life when he was hit by a car and died. His last thoughts were that it would be much better not to be human in the next life.

And so, Lu Chengye was reborn as a Labrador.

- Description from Novelupdates

He was an addict, a loser, a despicable human being.