God, I love this manga. Apart from the story, the details and the drawings - and even those alone are worth the reason to adore it - it's the complexity of each character that excites me... there are actually no good or bad characters. Just people who try in every way to achieve their goals, which however questionable they may be for those directly concerned are important and certainly worth trying.
The fact that these methods are often and willingly detrimental to everyone else does not automatically make them evil, at least not if seen from a superior point of view to that of "he harms me, therefore he is evil". Even the winged lion, despite being a demon, is not portrayed as an insipid creature at the "look at me how cool I am while I do my evil pose and laugh out loud doing totally illogical actions just to show how evil I am"; he was born a demon and therefore he doesn't have many choices how to behave, just as a fish can't decide to stop swimming to learn how to climb trees. Probably anyone who had the only chance to survive by deceiving others and exploiting them would do so.