Dungeon Overlord: Monster Girl Harem! - Chapter 19: Magic Cultivation and Fruit Porridge.

One day, I woke up only find out that I’d become a Demon Lord, an individual responsible for protecting a dungeon. The world I’d been spirited away to was one filled with violence. Gigantic monsters wandered through it and competed with each other each and every day for the right to survive. I had no choice but to strengthen my dungeon’s defenses in hopes of living another day—or at least that was what I’d thought. For some odd reason, I instead ended up spending my days in relaxation and bliss.

With the revival of spiritual energy and the breakdown of the order of species, it is a difficult test whether human beings can still stand at the top of the biological chain.

(There is already an old book, The Strongest Descends in the City, you can read it.)

- Description from novelbuddy

The world has changed, and so have the people.

“Even death can't stop me from reaching the top.”Alex clawed his way to the top through sheer hard work and ruthlessness, only to be betrayed by someone within his own group.Although he managed to kill the traitor, he lost his life in the process.But just when Alex thought it was the end, fate had other plans for him.Reincarnated into the world of a novel his girlfriend used to read, he was given a second chance at life.His goal remains the same, but this time, he awakened a mysterious system and surrounded by a harem of alluring beauties.Follow Alex journey through this vast new world as he uncovers the truth behind his reincarnation and the otherworldly goddess who made it all possible.