The Goddess's Personal Doctor - Chapter 347 Slayer!

The celestial celestial beings who lived for more than 100,000 years were born and reborn in a small monk in a human world.
His motto: “It’s not as good as a medicinal medicine for ten years of hard work.” “Even if you practice a copper-iron bone, it’s not enough for my soldier’s attack.”

- Description from Novelupdates

Dying in a tragic accident Marcus Ferrous gets transferred to a fantasy world of monsters and magic, except when he arrives contrary to what he expected he is now level one and a ghost. Left with nothing on a strange new world, Marcus will struggle with everything he has on his journey to get stronger and uncover the secrets of his new world.

This was a fragmented and disorganized world, this was a place that had been forgotten.

Based on the popular Vocaloid song .

Rin, a young angel (presumed female, but angels don’t have clear genders) falls in love with a young human girl, Miku. However, their love is considered taboo, and so, Rin makes a deal with the devil to be reborn as the human boy, Len, in order to be with Miku. However, their happiness together is short-lived, and even that soon ends in tragedy.