Can your dreams be seen outwardly and if so, can Sou remember it? Sure for both.
Can he use your character's innermost fears or desires to control/kill/violate him/her? Go for it! Though, let me know if he's gonna do this so that I know how to have her react.
Can he call upon your character at any given time to be used as a soldier? Sure. Just give me a heads' up.
By the powers invested by the Dark Forces of Nature, I now pronounce you a puppet. Agree? Y/N Y. Just give me a heads' up!