This work of art truly is a well done piece. The story is so deep and complex, and with so many twists and turns, I was surprised the mangaka had actually pulled this off without making this fall apart, and using cliche and cheap fan-service tactics to attempt saving the the series.
I give kudos to the mangaka for also accomplishing those twists and the increasing complexity of the story without using any twisted/messed-up material, and yet keeping those who read this engrossed and ready for the next moment of the plot. Sure there were a few unexplained moments and extremely minor plot holes......something this complex and this great is near impossible to pull off without any(heck there is no such work with a plot without plot holes). A great mystery indeed.
In addition, the characters are amazingly magnificent in representation, presence, development and purpose. He truly utilized all the characters, and did not kill any of them(I mean plot-wise, not life). He also managed to create an extremely dynamic character, who was at the same time static as well(an insane achievement, I am not telling who it is, READ IT)
The last thing i will say is this.....i think the author purposefully employed a shoujo-style artist for this.....just to give it another twist, which is great since the story has already achieved all the good points of a shounen manga, yet also considered what shounen lacks and took care of it...and also bringing this to the intellectual level for seinen as well........Due to this this manga is now in my top ten