Yeah I like Rasamee too cause she always lighten up Sila went he's sad.
You are right that Fang it's so moody, but think about it if you were her and a person you love won't admit that he's the person you used to know ten years ago. Also he's planning a revenge against anybody who hurt him ten years ago. The person you love change into an evil person and he's not the same anymore how would you feel?
I do agree with you what Bie did to Kwan was too much, but maybe there's a twist about what really happen that night.
The only reason she gets involved is she wants to proved that he's her P Tor, and that he's planning a revenge against anybody who hurt him ten years ago. She's also trying to make him stop and by the way Sila was the one who got involved with her. He made A bring Minta to him (it's a little exchange).
But I get sometimes watching this kind of lakorn can make you tense especially revenge lakorn. I feel the same way I just try to understand each of the characters.