As all fans of 07-Ghost would know by now, Eve is the daughter of the Chief of Heaven. However, there hasn't been any mention of her mother. I've been curious about who Eve's mother is, or if Eve even has a mother.
It's been confirmed that Teito is not Eve's reincarnation, but reincarnation or not, it can't be denied that Eve, no matter how coincidentally, looks an awful lot like Teito. What if it turned out that Eve has brown hair and green eyes like Teito? This brings me to my next point...
Brown and green are often associated with the earth, or nature. I think it's possible that Eve's mother is the goddess of the earth/nature in the series universe. Father-ruler of the heavens; mother-ruler of the earth: see where I'm going with this? O:)
Resembling her mother would also be a reasonable explanation for Eve's lack of resemblance to her father. Also, some important events in Eve's existence-her meetings with Verloren and her death-all occurred in parts of nature; she always met with Verloren in a forest, and her last wish was to be buried in a Flower of Eden field. Eve also clearly enjoys the outdoors and being surrounded by nature-perhaps it's not far-fetched to speculate that Eve's mother is never seen because she's somewhere in the background, silently observing and watching over her daughter. That would provide an interesting contrast to the Chief's blustery and confrontational nature.