The Assistant is the first encounter the player has with one of the residing ghosts of the Estate. She is easy enough to capture in the lantern, all you need is to find the bulb that will complete the device and she will willingly give herself up. She doesn't belong here as she sees it. The bulb is in the library and looks like a 1px dot at the moment, but the quest is finished and the SCUL shows one ghost captured. Noted but the white bar in the bottom it. Eventually that will look more like it's glowing.