Responses
Dude calm down. Me too.
I don't think he killed her for that reason, there was a scene of child Fl and her mother so that means they spent some time with eachother so the father probably knew that she was a demon.
I think there's a different killer (probably the emperor's men too) because father won't be talking about revenge if he's the killer.
The FL is probably the daughter of the demon king who his father fell in love with but had to kill because he thaught she tricked him or something and later realise it and ran away with the kid to protect her and now left her to protect the heart of her mother that ppl want to gain power or to get his revenge, idk just guessing.(づ￣ ³￣)づ