Story 10/10 The story is very original and not what you would expect from a ninja story. It took me 3 episodes to get into it, and a few more for me to really get interested. After that I was completely hooked. I liked that there were mini-plots within the main one. There were side stories like Raimei's and Gao's, but they were focused on just enough that they didn't distract too much from the main story. The only complaint I have is that the whole thing is pretty complicated. Some complex ideas aren't completely drawn out and it can take awhile to figure out (especially what the heck the shinrabanshou is)! It tested my patience a bit, but it was definitely worth it.
Characters 10/10 The main characters in Nabari no Ou are each very different individuals and I liked that their personalities differed. Despite the differences, relationships between the characters were meaningful and complex. I don't want to spoil anything so I'll just say that some of the characters you'd least expect are incredibly compatible and enjoyable to watch together (you'll know who I'm talking about). There was just the right amount of backstory for each character. I think that greater importance of a character = more backstory, and that's exactly how it played out.
Art 8/10 The animation isn't fantastic, but it isn't bad. There isn't too much detail and colors are mostly neutral. Like I said, the animation wasn't bad-it's well drawn and it's not really anything I'd complain about-but it isn't fantastic and gorgeous like Kuroshitsuji or Ouran High School Host Club for example.
Sound 9/10 I will have the theme song stuck in my head for all eternity, but it isn't a bad thing! I actually got the song and although I don't know what any of it means, it's a really catchy song! The ending theme was great too. The voice acting was phenomenal and they were really good at portraying the emotions of the characters. And I'm not surprised with J. Michael Tatum, Chris Patton, and Joel McDonald in the cast! Besides that, sound effects weren't to generic and I thought the music used really fit the mood of the scene.
Enjoyment 10/10 I thoroughly enjoyed every moment of Nabari no Ou and there is no doubt I'll be rewatching it soon (and again after that). The plot really kept me interested and the side stories kept me wondering how the other characters were doing. The characters were definitely the best part of this anime and I can't say it enough.
I don't think there's a specific group of people who would enjoy Nabari no Ou-it's kinda for everyone. There's action, comedic relief, drama, and supernatural themes. It's deemed a shounen, but I think girls would really enjoy this because of the character relationships and the bishies :)
Hope I helped!
