Demon King After the End - Chapter 21: Changing ways

When I became a rich young master, I had to enjoy it.

A data loving young man from Earth has an accident which transports him to a dark land filled with terrifying creatures and magical powers. Fortunately for him, he has a Biological Assistance Chip to ease his path. However, things in this bizarre and strange world are not always as they seem, and, though it is a tremendous asset, the chip doesn’t always work as expected. With all of the crazy creatures and magical mayhem around him, one can only wonder what the future holds for this young man…

A Federation Colonel with abnormal thoughts was locked in a dark room and met a little looney.

“Your whole body emits a scent that I dread (covet) and fear (desire).”

A frigid Colonel X little looney roommate: A sweet story of interstellar travel

- Description from Novelupdates

In this world, mastering runes is the key to becoming a cultivator. The ability to control these runes depends on the development of one’s Brain Domain. The more advanced the Brain Domain, the quicker and more precise the rune control, determining one’s potential as a cultivator.He was a boy from the slums with slim chances of rising above his station. Despite knowing his limitations, he worked tirelessly, driven by his dream and gratitude towards a childhood friend who helped him secure a spot in a prestigious high school. However, with a less developed Brain Domain, his prospects for further education and becoming a cultivator were bleak. His hard work seemed in vain when, six months before the crucial entrance exam, the girl he cherished rejected him, claiming their worlds were too different for their paths to cross again.But then, everything changed when he found himself engulfed in a mysterious ocean of golden runes!