I seriously thought of rating this full stars when I started seeing this anime but around halfway everything went wrong for me.
The anime is truly a battle between two great and intelligent minds who want to kill each other. The episodes are all thrilling to watch and I personally loved it but around the second half one of the centre character dies and are replaced but two other who couldn't fill his gap completely. That's the sole reason I didn't give full stars. It's still a must watch anime if you ask me.