IMMORTALITY (chara and male reader adventure)

(Y/N) and Chara were two kids living on a small orphanage, Chara had hate on her heart due to all of the negleting, and (Y/N) was brave to the heart, she saw hope on him, and wanted to try for a friend, that's what they became for the whole eternity, bad things happened and good things come back in return, they turned into Vile bloods, and served the queen for centuries, until they came back to their original world.

This is a universe that i was thinking of, the only thing that i'll insert is character and a few elements just like Cainhurst from Bloodborne or the Undertale story, but the characters i'll build their personalities and storys to this universe.