Pls help

Ok I read this manga a couple months back it’s about this skinny boy/girl. (Saying he has both he doesn’t switch in and out I don’t know what it’s called) His mother calls him a witch and is terrified? Of him? Or just flat out hates him. The father though loves all his kids. Not sure but a war started and the father went out to fight I’m not sure if they are royalty but there is a scene where the father is beheaded after being told by this queen bitch that his son was dead or something the father is overcome with grief and sobs, and his head placed on a pike. The skinny boy(girl) becomes bad ass, like some kind of war god, goes into the castle roof where his fathers head is and kisses his lips. He adored his father like crazy saying that his father was his light, well he keeps on being bad ass . Something led to something he(she) ends up with the king of the enemy forces, they were like it’s fate that were always meeting in this garden or something. The king is meek and his wife is very bitchy and kinda a pain in the ass.
Well the king loves likes the guy they don’t know each other’s identity for a while.
The boy has black hair, skinny and smallish eyes, looks androgynous, he wears tight black clothes.
I hope this is enough.