This is Hiem, the first tail of the Paper 9 Tailed Fox.
Hiem was originally a human like you and I, but because of mistakes he made in his past life, the world he once lived in vanished, leaving only fragments and memories. It wasn’t until he met someone special that he received a second chance and began rebuilding his home.
He now searches the universe, collecting the souls of those that are lost to bring them back to the realm he found. Each soul he aids adds a new piece to this world and they leave behind a letter to be read by the god that helped saved them.