What is the name of this book?

[Bryek]

so I have this series of books I read a few years ago but I don't think I finished it but I can't remember what its called.

so the first book is about three people:
the first is a girl who is the daughter of a Thatcher but ends up running away from (something) and was supposed to die after jumping a gorge but something carries her over it and she escapes. she ends up at a place that raises race horses.

rhe second character (i want to say his name is Amon or something similar) he is a different race than the people in the city by the ocean. he is sold to a woman who trains him to be an assassin but he can se the dead (i think). he ends up at this woman's house who reads fortunes with bones and finds out that he can do the same and ends up following her out of the city.

the third is about a girl and her younger brother. she kills her mother by opening her window while she was passed out in her room in the middle of winter. she is half and half of the two races.

they are all drawn up north to some prophet.

I hope that isn't too much detail and mixed books up. if anyone can give me a hand, that would be great.

thanks

[Bryek]

If it helps, the male character (eventually) goes into this secret area and learns about the religion of his people where the men bathe in this water that changes their heads into animal heads and then they celebrate by dancing around a fire.

The first girl, her name starts with a B. She starts having dreams about the guy who invaded their land and why he disappeared.

[Mapleson]

When did you read it and was it new or old when you did? I'm assuming you read it in English?

[Bryek]

of course. I figured it out the other day finding someone elses "whats that book"

its The Castings Trilogy

his names ash, not amon...