Let me clarify first - this is a piece of art & one of the best thriller, mystery, horror themed BL I've ever seen along with DFF. So please watch it first & then read this. Dan, whom we're treating as a main lead, THE GOOD GUY, is actually a bisexual playboy. When Nai kissed him, he didn't stop him & gave him hope saying "I'm your partner" the next day. Otherhand, we can see he liked Cha-aim too. And when the monster pleasured him in his dreams, he enjoyed that to the fullest & kept saying, he isn't bad. Nai's father fulfilled his promise by giving him to the monster, so Dan belongs to the monster. But the monster doesn't treat him like his child, he treats him like his lover. This is actually the lovestory between monster & Dan. I like the ending so much, I want to see more actually, Trin is back in Dan's body, now he can be in relationship with his love interest (drama teacher) & my favourite character is Nai, the pure soul.