Ok well it seems you want an anime series that generally dark in tone, hmmm (no manga?).
Alright we'll let me be the first to say that Full Metal Alchemist:Brotherhood (the definite version) is by no means that dramatically emotional as it goes on. If you want arms and legs getting torn off, necks and shoulder veins being slit, and "Bad Wurdz" its got it all!
But if you don't like Full Metal for whatever reason then why not watch, Cowboy Bebop! A series where each episode is better than some whole series! At 26 episodes with hardly any filler (its not bad as Naruto filler, lol) the excitment and intrigue never stop until the closing finale!
See You Space Cowboy