God Ash: Remnants of the fallen. - Chapter 563: Devilish (1).

The mortal body, metamorphosis, longevity, immortality, and eternal life. These five realms, step by step, reveal themselves in front of you. As a normal person, how can one try step by step to reach and open the door to eternal life?

Between the heaven and the earth lies the mortal body, the mysteries of metamorphosis, freedom of longevity, the power of immortality, and the hope of eternal life. A story filled with endless new magic, a new world of immortal styles, people, demons, gods, fairies, magic, kings and emperors. A world of love and hatred, revenge, and mystical battle, all in “Eternal Life.”

- Description from Novelupdates

Xia Yuqing is a shut-in+fujoshi from the 21st century. After an accident, she transmigrates into the body of a young princess forced into a political marriage to another country.

High-school student Koremitsu Akagi finds himself attending the funeral of Hikaru Mikado, who had died in an accident during Golden Week. He’s not sure why he’s there, as he only exchanged a few words with Hikaru at school. However, Hikaru doesn’t seem to be completely gone from the world, as he comes back as a ghost in order to fulfill a promise to Aoi Saotome, his fiancée. Since Koremitsu is the only one who can see him, he asks him to carry out his promise in his place.

Complying with his request, Koremitsu tries to fulfill Hikaru’s promises to the rest of his “girlfriends”, helping them overcome past misunderstandings and repair broken relationships.