From Protector of the Grey House:
“And then you would return.” He paused. “I know the nature of a life led by revenge, Natalia and would be worried if all you had was revenge.” His hand covered the stone hanging around her neck. “If you didn’t have something greater holding you to my house, I would not have given you rank. You are loyal to your mother and wish to kill one monster, but you are still here in this limousine, allowing a vampire to hold you close enough to drain your blood…”
He pulled her arm to his mouth, bit into her wrist, and made her gasp. He drew three swallows of blood, pulled away, and staunched the flow of blood with his handkerchief. “…with no fear for your life. I have no doubt that if you left my house to find Donald, you would return to me. You are loyal to me and to my house. You will return when you leave to find him.”
“You sound so sure that I’ll win.” A bit of doubt crept into her voice.
“You have the sword. And if you didn’t have that you would have your intelligence, and your determination. Nothing will stop you from winning, Natalia.”
“What will stop me from dying in the process?”
“Your will and determination, and the knowledge that you might come to me and live forever, should he try and kill you.”