It's Actually Not Easy Wanting to be a Supporting Male Lead - Chapter 9 part7

The eldest daughter of the Li family is beautiful and sassy, ​​she took space materials to flee famine, and after going through many difficulties in war, disease and epidemic, she united with her family to regain the glory and harvested a beautiful boy.

- Description from novelbuddy

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.

Arriving in a new world where the steam industry was booming, he inherited a three-story apartment on the capital’s royal square, took in someone else’s cat, and listened to the whispers at his ear, ready to witness this mysterious and bizarre era. The epic of the Sixth Era was about to commence, and behind the curtain, The Chosen One was destined to step into legend. Old Gods, Relics, steam, witches, detectives, ancient secrets, the Era’s brilliance... “Would you like to play a round of Roder Cards?” Time engraved the hours, as Silvermoon illuminated the shadows. I compose your legend, you whisper your verses to me.

Mana finally arrived in our world after being delayed for unknown reasons, causing the evolution of everything that had life.

Humans, plants, and monsters all evolved, ushering the planet into a new era in which old laws no longer applied and the only law in the world was the rule of the jungle, where the strong preyed on the weak.

It was a question of whether we, the 'rulers' of the land, would be able to maintain our position and adapt to whatever came after our planet's awakening, and if we did, was that the end?