The Shadow Monster and His Groom

Dion needs to get married for his family's sake. That sadly means he has to say goodbye to his first love, the child that always appeared in his dreams. However, after their conversation, ominous things start happening around him one after another. He's gradually losing his mind, to the point of considering taking his own life, but thankfully someone appears to save him. 'I am your groom.' He can't see his face nor does he know his identity, but somehow his relationship with him feels familiar and comfortable... 'What on earth are you..?'