omg, are you serious, people ?
The whole thing is just about despair, and Kurono doing his best in the worst situations. The manga describe the evolution of that Kurono that wanted to became as he was before (never thinking about defeat), and everyone one following him for this side of him.
Even kaito is only built on this idea of becoming like Kurono was, that's the point since like, chapter 2?
All the characters were here just to support this thing, because it's all about despair and hope, the manga is wonderfull because of that.
The manga didn't spend a single chapter aside of that, and you people just wanted a lovely story of the characters in a totaly non dangerous situation?
Just because you didn't have the epilogue you wanted doesn't mean this is a bad end.
If you think this is a crappy ending, it's because you didn't read it right!