Darker than Black: Kuro no Keiyakusha, Fullmetal Alchemist: Brotherhood Recommendations
Similar dark premise as far as story lines are concerned, main characters are different but seem to both fit in their perspective storylines well. Common misconceptions from the main charcters, help thicken both plots. Great action scenes of the use of superhuman abilities, as well as the idea of an alternate reality. Overall DTB was an awesome anime, what else would you expect from a BONES production, but greatness.
Both DTB and FMAB have scifi involved with their action as well as sacrifices. The law of equivalent exchange for alchemists in FMAB is similar to the payment that contracts must pay which is giving up something for their powers in DTB. Both also have a myth about somehow breaking off that law or rule: in FMAB alchemist search for a way to ignore the rule of equivalent exchange and in DTB contractors and the concept of delaying their payment. FMAB has the philosopher's stone and DTB has the meteor shard which work as amplifiers for their powers. They are both also in organizations who
It's an anime done by the same studio and I find it has similarites with Fullmetal Alchemist. It's not on the same level but it's still a very enjoyable action anime like Fullmetal Alchemist. This show has an excellent sense of mystery, world, story and amazing action scenes.
Both are from worlds where people have super-powers, and is about a story where there is a "bigger organization" is hidden and controling from the hidden eye. A pretty serious dark undertone, but Fullmetal Alchemist brotherhood has some humerous moments to compensate