Black Blood Brothers is a show about vampires. You know, vampires? The ones that gain their power from the full moon, create armies of zombie slaves, can be deterred by silver bullets, and, occasionally, morph into wolves?
I hope I'm not the only one who is confused.
Black Blood Brothers
Created by: Group TAC/Studio Live
Published by: FUNimation
Release Date: August 31, 2010
Clearly, the creators of BBB didn’t pay much mind to any sort of existing vampire lore. Luckily, this didn’t deter from the quality of the show otherwise. So let’s just get it out of the way now -- these are NOT Hellsing’s vampires.
Once I was able to get over my utter vampire culture shock, I was able to focus on the characters. Our protagonist is Jiro, a young-looking man who dresses like a mix between Vash the Stampede and Carmen Sandiego. Due to the strict rules of shounen anime protagonists, Jiro also happens to be one of the oldest, most powerful, most badass Black Bloods (aka vampires) around. His travels are accompanied by Kotaro, a young vampire who dresses like Quatre from Gundam Wing if he were ten years old. Even though they have NOTHING in common -- dark Jiro burns in the sun, melts in the water, and drinks blood while fair Kotaro loves sunshine, swimming, and sweets -- they call each other big brother and little brother, respectively. At the start of episode one, the two are on a journey.
This is where it gets complicated and many strange terms are half-heartedly dashed around with no explanation. There’s the Special Zone, a place where humans and vampires can coexist peacefully, a place Jiro and Kotaro are trying to get to. There’s the Kowloon Children, a deadly lineage of infectious vampires who create mindless zombies out of anyone they bite. What about the Order Coffin Company, a group of Red Bloods (aka humans) who act as the first line of defense against unruly vampires. Seriously, this story should come with a glossary. (Luckily, the Wikipedia page does include one, albeit with spoilers.)

So, if you’ve stayed with me up to this point, Jiro and Kotaro, who are Black Bloods, are stowing away on a Company ship in order to get to the Special Zone while Red Bloods from the Company are worried about a Kowloon Child outbreak. Got all that? Good. Because now it’s time for the good part.
Despite how strongly I’ve been criticizing the nuances of Black Blood Brothers, I really enjoyed it as a whole and, in fact, watched it all in one day, and then again! And believe me, it’s better the second time. Once you manage to wrap your brain around the fact that 1) the vampire lore is perverted and 2) the lexicon is confusing as crap at the beginning, you can more fully enjoy the drama and fighting.
Because if there’s anything BBB does exceptionally well, it’s the fight scenes. Sure, Jiro is supposedly invincible, but that didn’t keep me from tensing up in suspense each time he went into battle. Where a lot of animes might pansy out and have a ten second fight with a few sound effects, Black Blood Brothers animates each conflict with precision. You may think you’ve fingered the clear winner, but prepare for twists and turns.
And Jiro isn’t just fighting faceless Company drones or mindless Kowloon Child zombies, either. His opponents have well-considered backgrounds, motives, and special abilities. Sometimes, it’s unclear whether his opponents are also allies -- the beauty of the series is that, as in life, there’s a mix of good and bad in everyone and everything, not always apparent at first. Some of the notable characters they meet include Mimiko, a human whom, while contrived to be Jiro’s love interest, isn’t at all boring or a burden; Cassa, a Kowloon Child with whom Jiro has a long and mysterious past; Kelly Wong, a tough but kindhearted vampire who is also on her way to the Special Zone; and Zelman Clock, an unpredictable vampire with flamethrower eyes.

In the end, Black Blood Brothers isn’t your typical “humans vs. vampires” drama. All the humans and vampires that the brothers meet have the potential to be good or evil, friend or foe. And, you will want to stick with Jiro and Kotaro while they’re finding out which is which.
** Minor Spoilers, mostly backstory **
Except for the Kowloon Children. What makes them so dangerous is that anyone bit by a Kowloon Child, human or vampire, becomes one themselves (and if weaker than the one that bit you, become a thrall to them, which is why many are mindless zombies). That is what makes them so dangerous, is that Kowloon Children can spread like a plague, quickly overwhelming a population.
The pivotal event in the backstory of BBB is that 10 years ago vampires were as we see them in most vampire fiction, hidden from the world, pulling strings of human society in secret, and assumed by most people to be fictional. Then out of the blue the Kowloon Children appeared in Hong Kong, and the truth of vampires were revealed to the world. To keep the Kowloon Children from spreading across the world and threatening the existence of the human (and ultimately vampire) races, other vampires too revealed themselves to the world and helped the humans defeat the Kowloon Children. As you might expect, Jiro was one of those vampires.
Hong Kong was basically destroyed in the ensuing war, and most of the population fled to Tokku, the Special Economic Zone. In the story it's a large artificial island in Tokyo Bay that was given special economic independent status, similar to Hong Kong. It also becomes the only place in the world where vampires have legal protection and can publicly reveal themselves.
I haven't seen the anime so I can't comment on it, but in the books, the fight scenes are really well-written and exciting. If you can read Japanese and enjoy this genre, I recommend them.