Togabito No Kokuin summary:

People say 'I love you' to someone. But I wonder where that love is. A beautiful boy named Mikage, who looked like a ceramic doll, appeared in front of Kanna, a young man who could not find what he was looking for."If you want it, come to me. I will love you."This is a story of those who have committed a sin, gone off the path of humanity, and have an imprint called a "holy mark," a proof of their sin, on their bodies.