I don't like this story, I don't like it at all.
Why am I here writing its review while I'm supposed to sleep?
This manga is one hell of a roller coaster. It pulled you in, and once you're on, it's a non-stop ride towards the end. The end is kinda weak, in my opinion. But overall it's still a good story. An old shounen story with a dark theme (and a lot of blood, seriously, blood is everywhere in this manga). You who like 90s kind of shounen and martical art would enjoy it. I did enjoy the ride, but tell me to read it again? No! No! NO!!!
Because it hurts so, so much. Too much killing. Not that it's not neccessary, it fits with the gruesome theme of the story. But still too much, and it gave you hope, and took that hope away from your hands. I just realized, at the end, my hands are all full of emptiness, as the OP has stated.
I really like Fujita Kazuhiro story because the plot is always unique. Karakuri has the best plot and story telling in all of his 3 works I've read (Gekkou, U&T, Karakuri), but I would recommend you try out Gekkou, his latest completed work. His story planning and character building has made great improvement (but there're still plot holes here and there).