Story: 6
Let's start with the positive aspects:
As the synopsis suggests, this story is about ninja. Well, it's not ninja in naruto fashion, but in clan-sort-of fashion with ninja as bodyguards. I found this realistic and interesting. Another nice thing about this manga is the development of romance. In my opinion, it's nicely paced, not too fast. Most shojo manga I have read had this crazy pace of budding romance to the point. This manga, however, made me relate to and see how they (at least the male lead) are attracted to each other. Though I have seen some reviews finding this pacing too suspenseful and frustrating, so if you're an impatient type, then be warned.
As for the negatives:
For one thing, it took quite a while for real story to start. You can say the development of attraction is quite slow, well, in the opinion of some people.
Also, while there are many twists, some bits and pieces were so 'twisted' that I was at a loss.
In general, though, it's pretty decent and better than most shojo manga of this time I have read. Let's say most mysteries would be answered at the end.
Art: 8
The at is excellent, eye-candy shojo art (and not crappy shojo art). It started off as a comical style and getting better and BETTER later.
Character: 8
The male lead is probably the most important reason why I enjoyed this manga. On the surface, he's shy and cute, genuinely hating violence, but when it comes to protecting the female lead, he would do absolutely everything and remain loyal to her. I won't spoil anymore, but at one point you sort of know his character well enough to know how he actually feel despite his actions.
The female lead may appear an annoying Tsundere/Hime character at the beginning who doesn't give a s--- about the dedicated male lead. But you will soon learn that she has a reason for acting untrustful like that. Over time, she grew up.
Overall, I think I could see character development in them, but it is questionable if it is well executed or not.
As for the side characters, I think they are pretty average shojo characters, but none of them are really disagreeable (though you might find them disagreeable at first).
Enjoyment: 9
Despite all the flaws, I totally enjoyed this manga. Must be because I have a thing for nice-but-actually-badass charcater, though! The male lead is totally my type.
Overall: 8
While I think it doesn't deserve a 9, I really enjoyed this shojo manga so much that I think 7 would be too low. So, yes, if you like somewhat suspenseful drama, go for it. But if you're looking for master-bodyguard rom-com or naruto-like ninja action, then no. Oh, but if you're looking for something like Nabari no Ou, then I guess it is pretty similar in that it's more character-oriented than action-oriented.
