I read a fantasy Book about 10 or so years ago that I really want to find again. I will try and list as much info as I can remember about the book.
The Book had a medieval Tone. A kingdom is being attacked by monsters coming from a massive shadow spreading over the land. The king of the kingdom gets stabbed by one of the main characters that has been "possessed" (he can hear the monsters' thoughts somehow) by the shadow and he takes over the throne. The new king leads his people to another kingdom to escape the shadow (the other kingdom might be an elven kingdom).
Somehow, the king is helping the "shadow" to save Himself; the king sends one of the army's heroic soldiers to a mountain where he gets turned into stone.
The same warrior is also considered a primary character of the book (I think along with a girl as well).