Fullmetal Alchemist, Pandora Hearts Recommendations
Pandora is abit similar to FMA, Ed is a person who as a child had his father leave him , while in Pandora hearts, Oz's father abandons him and though they are entirely for different reasons, it still has the aspects of their father's being a mystery. Both FMA and Pandora hearts have deep plots such as Homunculus being mysterious group that have unknown intentions, while in Pandora hearts, the Baskervilles are a family whose leader is unknown and their intentions also unknown. They both contain fights which explore characters,different abilities as well as the theme of immature main characters who start growing out of
Both have pseudo-European settings with a bit of light "magic"; the main character (Ed, Oz) is forced into working for an organization after having a horrible experience. They both have to prevent a repeat of the past which could destroy the world.
Both series have large casts of interesting characters on both the good and bad side, as well as ones who you don't know which side they're on; the main bad guy stays in the shadows for a long time. Have an alternate dimension (the gate, the abyss). Have heavy mysteries, plot twists, and suspense. Don't have a huge amount of
Both series seem to be contained, shorter series, not long manga like Bleach or One Piece. Each involves a consispiracy with fantastical elements. The center of both is a boy, although Ed and Oz are supposedly a couple years apart. They both deal beautifully with the issues they raise, and both give us unbelievable twists. Most importantly, they are both fantastic manga, some of the best out there.