Well, first there are a lot of reviews that totally trash this series and while I understand from they are coming from, I can't say that I hated this manga.
On the contrary I really loved it because of the same things people are arguing about.
Its complicated and full of flash backs and sometimes you can't really understand what is going on: I ADORE it.
It keeps me on my toes and makes put an effort reading this and try to figure what the characters are thing about.
The legend and storical parts may be a bit confusing but nothing that a bit of research can't fix and its not really necessarily if you follow the flow of the manga l.
Its not a normal manga, don't search for a linear story and everything tied nicely together.
You won't find much of that here. Its confusing on purpose and full of flaws that imitate human morals and opinions, because what is Human is important in the plot.
But if you want a story full of misleading and dark themes, this is your thing.
Yet you can't read it in public! Its full of breasts and panties shots and other stuff you won't like getting caught reading by friends or coworkers.
Some characters I loved more than others and if you love characters besides the main protagonist that is very well.
The author made it that way and I respect that.
Especially the part that the main character is there to be the catalist of the current story, and ties past and present together in some ways... He doesn't have to be the hero nor the most important person there, there are plenty of other characters that are heroes in very different ways so you can pick who you love the most.
I won't say anything to anyone if this is a good or bad manga.
Read it yourself and judge if its a good story for you.