As an anime based on manga based on a novel, Mirage of Blaze had quite a bit of material to work with. 13 episodes seem short, but I have seen many elaborate storylines perfectly deployed in such time. I have also seen many storylines hazardously try to fit as much nebulous content as possible without direction... and Mirage of Blaze is yet another one.
I have rarely witnessed so much energy spent in saving on animation. The drawings themselves are pretty but had a very limited amount to work with; characters walk by moving up and down on a background and have no body language whatsoever. The action is done by applying various filters on the same drawings, and even the backgrounds are exploited beyond their limits. The instant-anime technique never seems to works for me no matter how well they try to hide it. I had come to expect more of Studio Madhouse. That same, cup-o'-ramen style was obviously used during the conception of the storyboard. Loosely based on Japanese history, the writers had a pretty good idea with the basic tale, but the end result is a complete mess. Plot elements overlap and pile up, while the list of similar-looking characters continually expands until the very end, as if the cast learned at the last minute that the show was only going to be 13 episodes. A three-OVA sequel was released two years later, but the damage to the television series is irreparable.
To appreciate this anime, you have to focus solely on the relation between Takaya and Naoe. The intensity of Naoe's internal struggle, though pretty disturbing, is what drives this anime. Unfortunately, the first hints appear latterly in the series. Another thing to watch out for is the moral conflicts these samurai spirits face as they rob humans of their lives to live on; not something you see in every anime.
With some good moments and a lot of bad ones, it is just too easy to disconnect from Mirage of Blaze. Being pulled left and right for no reason is sure to put off anyone interested in following the storyline. Those who just want eye-candy are also going to be let down, unless still shots of pretty bishonen are all that you ask for.