Ying, second born of the twins, son of Estaphis, is the Guardian to Hell. Unknowingly, his overwhelming sinful nature was caused by his brother Yang, before they were born, as all the essence of good was given to the Guardian of Heaven's Gate. His frustration comes from him blaming himself for his Mother's death, believing that his father looks down on him for it (which isn't true) and that he is judged by those around him for his "crime".
His depressing past does not keep him from being full of energy. Ying enjoys women a bit too much and has often been beaten down by Ixe who detests his nasty tendencies. In turn Ying is not very fond of Ixe being that he is half human who was raised by his father and felt as though Estaphis held the Earth Sage in a higher respect. Feeling overlooked, his jealousy turned to hate.
It seems as though Levi (the sage of water), at some point in time, took a liking to the satyr (Ying) but he has no interest in her as a "Woman", after all, she hasn't grown enough to "Develop". She is, however, the only one Ying has a soft side towards Maybe it's her innocent happy attitude or because he believes she is the only one who truly cares about him for who he is.