This review contains medium SPOILERS: I will give away the premise that is established after about two volumes. Basically, I am going to tell you what "Shiki" means. No less and no more.
However, I think that this being a mystery manga, you may enjoy going into it as blind as you will. If that's the case for you then do avoid reading this review (any sort of information on the manga for that matter); go ahead and give it a try!
Shiki is one of those works which demonstrate beautifully how a concept that seems old and uninteresting can be revived to make for a refreshing
setting. When the village of "Sotoba" is haunted by mysterious deaths everybody seems clueless concerning the origin of the proclaimed epidemic. Only a few individuals have the bravery and recklessness to dare think it could be the "Okiagari" - later named Shiki - causing the calamity. These so-called Okiagari are people who were once dead but have risen and are thereon blessed to live forever but cursed to feed on human blood.
This premise alongside with each characters motivations is what drives the plot. What keeps the story so lively is the excellent writing. Each chapter will focus on one particular character. And although these tales appear to exist independently of each other, they slowly begin to intertwine. Another good feature of the storytelling is that, as a reader you are never given the complete picture. Leaving you in the dark for most of its duration the manga makes for a very suspenseful read.
The concept which this manga is centred around (vampirism) comes across as ever so fresh. That's because Shiki takes a surprisingly serious approach to the theme having its characters deal with many of its social and moral consequences. As the Okiagari are not simply used as a setup for an action or a horror story but are treated like the dilemma that they really represent, everything becomes that much more believable as well as thought-provoking. The story is rich in allegories and all sorts of symbolisms relating to questions of justice, ethics, human nature and many more.
In this turmoil of justice and injustice, compassion and instincts, survivability and principles, each (main) character has his or her own point of view. Some of them more clear-cut than others.
The good thing about the cast is that it's big and it's rather diverse.
But while it is the convictions of the key characters that push the plot, these lead characters themselves do not undergo as much development as one could have expected. Especially considering the complete 180° (or is it 360°?) shift that the plot with its various twists achieves.
Even though the themes and topics are all there, sometimes one might wish that a particular point of view (say the moralist's, the nihilist's, the speciesism's) be a little more openly expressed by a specific character. It's oftentimes you contemplating, not the characters.
If their contentual expression may be lacking at times, the characters' visual appearance certainly doesn't. The art style is something to get used to with very spikey hair and largely exaggerated facial and bodily traits. I think that the general art style is probably subject to taste but if you keep an open mind I definitely think you too will appreciate the great variety that it offers. If anything, I think it adds to the feeling of the manga.
In the end, what sets Shiki apart from other series of the supernatural genre is the commitment to explore the actual implications of a pop fiction topic. This story is executed candidly, brutely and without any sort of melodrama whatsoever. There are next to no comedic moments in Shiki, instead numerous shocking, moving and memorable ones.
Although in my opnion the (very) end makes the symbolism a bit too amiguous the rest of the series is an absolute treat. Even if you will be left alone to do so don't miss the chance to ponder over what is means to be a Okiagari, or a human being or both.