Descendants of Darkness is based on the manga of the same name. It follows four major story arcs of the manga. Three episodes comprise each of the first three arcs while the last four episodes focus on the fourth. Since the anime leaves off where the manga caries on (the manga isn't finished either), the ending doesn't really offer a true conclusion and a lot of questions are left unanswered. Fans of the manga might also be disappointed that a lot of the manga's characters are either left out or shoved into the background.
Despite these unfortunate circumstances, I think that the anime more than does the manga justice. In fact, I find it to be an improvement over the manga. While some of the humor and silliness are there, the anime takes on a more serious tone, capitalizing more on the angst, mystery, and supernatural element of the story. The art and music are also absolutely beautiful! Descendants of Darkness has a superb soundtrack which is well worth downloading or even buying! Aside from the characters being beautiful, the monsters and magic are also magnificently rendered. Even though it isn't really a fighting anime, the action sequences should be awesome enough to please those who would otherwise be bored with the drama.
The series consists mostly of fairly mediocre characters, yet it has what I consider to be one of the greatest villains in anime history. Tsuzuki and Hisoka are the protagonists of our story. They are likable characters overall. Tsuzuki is a real sweety despite being a little bit dense and childlike at times. Hisoka has a little bit of an attitude problem at first, but once it becomes apparent where he is coming from, you can't help but sympathize with the guy. Watari and Tatsumi are minor characters who had significantly larger roles in the manga. For the most part, they are just there. They don't really add that much to the anime, but they don't detract from it either. The Gushoshin twins are the only characters that could really be considered annoying. This is mostly because they seem a bit out of place (being two cutesy little talking birds in an otherwise human cast).
Our antagonist Dr. Muraki gets his own paragraph since no couple of sentences could possibly do him justice. He is the subject of much admiration as well as loathing from DoD fans, and he deserves every bit of both. Practically everything he does is just horrific and despicable, but he is so cool and gorgeous and entertaining that you can almost forgive him for being the monster he is. He desires Tsuzuki's body both carnally and scientifically. The scientific reason is revealed later and it gives Muraki's character quite a bit more depth, though you are longing for much more once the anime ends.
While the show isn't technically shounen-ai (gay male romance), it contains a lot of hints and fanservice. It is very easy to read in an attraction between our two heroes. I personally believe in this attraction, but other fans are free to form their own interpretations. Muraki is much less ambiguous and regularly molests Tsuzuki. This lust Muraki has for Tsuzuki is clearly one-sided, but it makes for some rather hot homoerotic material (even though nothing overtly sexual actually happens).
The show masquerades a bit as a mystery series. In reality, the mysteries aren't really any big puzzle. As the audience, we basically know that Muraki is behind everything (with the exception of episodes 4-6). And while the story isn't particularly imaginative as far as anime goes, the characters and the art make it more than worthwhile. All in all, I can't think of any reason to dislike this series unless you're either homophobic or a hardcore manga snob. But we can't please everybody, can we?
