Legend said, if demon meet someone in 'Blood Moon' who comes just once in many decades, that would be their love. Demons is very loyal to whoever it is they meet in 'Blood Moon'.

One day, you're walking alone and saw the moon looks red, as you noticed the moon looks red, you saw a handsome man near the sea. His eyes crimson dark red, he has a wings, tail and horns. Kim Seokjin, the strongest demon that exist, his demon form active cause 'Blood Moon'. He love you immediately.