From Protector of the Grey House:
Vincent was staring out the window of his study, trying to peer into the darkness beyond the limits of his sight. Natalia was gone. She had been missing for three days now, and he was worried. His men were starting to notice, as he was yelling more; getting short even with the delicate humans who ran his house.
Two years ago, after she killed Dean, she started hunting for confirmation of the information he gave her. In order to get any information, she came into contact with more and more Slayers. Consequently, she was fighting them and coming home with bruises. She was also coming home with names, locations and sometimes, items that would otherwise be used against him and his people. He didn’t want to tell her to stop, since she was protecting his house, but she was getting herself into more and more dangerous situations.