I just finished watching xxxHolic (courtasy of YouTube) and on Episode 22-23, there was a woman who pretty much was causing Watanuki to get sick, to the point where he was going to die. Yuuko was going to mention what she was, but because Watanuki didn't want her too, she never did.

Does anyone know what she was? Another thing, Maru and Moro, they mentionned they have no soul, so what are they, and why will they not last long outside the fence of Yuuko's shop?

Ah, the curiosities! Anyone know and care to fill me in?