Well, where to begin... When the series first started, it seemed as if it would be a violent shounen fighting-type series with a Battle Royale kind of tone. It was all fine and good, and seemed promising, with some stylish artwork in areas (the part where the fat guy explodes in the first chapter is pretty cool). Sure, it wasn't totally original at that point, but it had a lot of good ideas.
The violence and ecchiness kept a decent balance with a pretty typical story up through about chapter 7 or so, when the art started suddenly looking a lot more rushed (earlier chapters also had some rushed artwork, but the quality drop was fairly extreme... As another reviewer stated, it's a little frustrating, because there's terrible rushed art right next to awesome detailed art in the series, often within the same chapter... but anyway). At that point, things began to take a much more confusing turn with a lot of cryptic statements and hidden motives, but still, as long as they explain everything eventually, it's all good right? Well, I'd like to say that everything was explained and everything got better... but it didn't. In chapter 8, seemingly random events and characters appear with no apparent reason, then by chapter 9 the series just jumped the shark with some of the weirdest stuff I have ever seen in a manga (I won't say what to avoid spoilers, but let's just say it involves flying boobs). The confusion continues through chapter 10, with extremely complicated political relationships that were never shown or explained earlier. Meanwhile, all side characters are completely left in the dust as the focus shifts entirely to the two main characters and some other characters who until then didn't have much role. It all ends up in a conclusion that's hard to wrap my head around. It seemed like it was trying to present some political view or moral, but it was a bit hard to understand (RL war is bad but fantasy war is good? I dunno).
In any case... Despite how this review is almost nothing but complaints, I can't say this is a bad series. It was genuinely thoroughly entertaining for the first volume with all the different Chivalrous Powers and factions, has some awesome art interspersed in the bad art, and is nice and graphic. Even the second half of the series isn't really BAD. There are certainly some memorable scenes here and there. Actually, despite my complaints, the second volume was probably much more memorable overall than the first volume thanks to a number of scenes that were either just viciously brutal or well-done. But it's all so hard to understand. I don't mind it when an author leaves some details up to the reader to decide, but when it's not just little details and is half of the story, it's just confusing.
It probably would have been better with a few more volumes and if the author had kept to the Battle Royale theme. With that, the side characters might have been able to receive some more development, because some of them were actually quite interesting when they weren't just posing for underwear photos or punching their girlfriend's breasts. Maybe the main characters too, since their development isn't exactly the strongest, either. Maybe we would have gotten better explanations for some things that just left a "huh?" feeling. It just feels like a lot of untapped potential, and it's unfortunate, but it's important to try to enjoy it for what it is. Overall, it's a strange manga, and a mixed bag in a number of ways. But if you want something graphic or don't mind a confusing plot, give it a shot.