Vivian saw the shadow that was behind the wall. It wasn't that it moved but that was the only wall that had a bigger shadow that fell on the ground that the rest of them. It was the ghoul who was hiding behind the wall.
Remembering how Nicholas had told them that one of his ghoul named 'Everest' had been not listening to him, she turned around to look at the ghoul that was still behind the wall which hadn't stepped out into her complete view. The Lord had been worried as it was out of character for the creature of the dead to behaving like this and this made her wonder if the ghoul had come to see her without letting its master know, or was it another ghoul? When she had asked Nicholas on the name of the other ghoul he had called it 'Narcissus'.
The ghoul was to listen to Nicholas' commands and words as they were part of him. They were born from his pain and anguish after his mother's death.