Story: 8/10
I'll mention it's flaw first, it has some pacing issues, especially if we talk about relationship or romance between MC and the princess. it's not that bad though, I rarely find good romance in this kind of genre, some might even find the conclusion satisfactory(I won't spoil anything here). The main story itself is not half-bad, the tale of "the worst one" is pretty intriguing.Although the plot almost overshadowed by the ecchi scene here and there, but it gets better and more serious(in good way) towards the end.
Character: 8/10
I like most of them, the female pair (the princess and imouto) make good comedy duo. but the most interesting one is the MC, he's cool and skilled, also he has some nice background story and development. some enemies and rivals are pretty decent, too bad we can't see much of their action.
Art: 8/10
I'm no expert when it comes to art in anime, but I'll say the battles animation are really great. each character has unique style and performed well in battle.
Sound: 6/10
I don't remember anything memorable, except that dude song in the opening is really lame
Enjoyment: 9/10
Well, I enjoy almost the entire show (especially the battles) and actually hoping for more, too bad no indication or confirmation for 2nd season
