This anime is amazing.
Darker than black is a neo-noir esque, action-packed thriller about a world where super beings exist, known as "contractors," and the many organizations they belong too, some notably being the CIA, MI6 and Japanese government.
The first few episodes don't immediately draw you in, however the tension and plot builds up slowly to introduce the setting. Sometimes it can get confusing, and I had to pause to google terminology due to the fact that not everything is explained fully. However, the animation is clean & simple and the soundtrack is jazzy.
What I enjoyed the most about this series is how interesting the main character is. Hei is a powerful contractor working for a secret organization. His daytime identity is Li Shengshun, a Chinese exchange student. What's interesting about him is that although he is extremely bad-ass, he is also has an emotional side unlike most contractors and can make mistakes. He's not super-powered like some anime protagonists.
This anime is not completely centered on Hei, but more on the different organizations and groups and how they interact. Which also gives him an air of mystery, as we do not know what he is doing.
Overall, the anime is great, dark in tone and has a great plot. It's set of characters are very three dimensional (it's nice to have female characters that have actual personalities for once). The story doesn't focus on romance nor sexuality, but more on awesome fighting scenes and its mysterious plot.
10/10