It takes first hand experiences about what it's like to kill within and sometimes without the moral boundaries of war, and gives real insight into how humans can be changed to accept doing it and the damage they can sustain and why. I think it's a must-read for any author that has characters that even think about going that far.
It really made me happy about my Twin Souls Shunsui's reactions and reasons for why he couldn't even strike his instructor early on in the series, and how he reacts when he actually managed to deal with a Hollow.
I also got to see all of Firefly and now understand why my sister thought it was so amazing when it was coming out. My main impression was that it was getting better and better with each episode, and that the two shows that never aired were the best ones. That amazed me... and the ensemble character of the cast was really wonderful. I have now bought the movie as well as the full series for my own. *laughs*
Yes, that does mean that I'm probably up for fanfiction for that series, now. I love the characters so very much.