Ghost in the Shell (often called GitS) is a sci-fi-y pollice thriller centered around Motoko Kusanagi, a member of the Japanese National Public Safety Commission, Section 9, which specializes in fighting technology-related crime.
She is capable of superhuman feats, as her body is almost completely mechanized; only her brain and a segment of her spinal cord are organic.
There are currently 52 episodes in all, and 3 movies.
Karas is a 6-episode oav that tells the story of Otoha, a former yakuza, living in a fictional version of Shinjuku, Tokyo which populated by humans and youkai (Japanese spirits). He is one of the karas- humans appointed as superpowered agents of the land.
The old Karas is dead, killed by an evil ex-Karas who now named himself Ekou. He started a series of murders against humanity by making his loyal youkai drain the body fluids from humans. Otoha ,a young man who just woke from a coma, is chosen to be the new Karas. Him and his trainer, Yurine, start the fight against the evil forces of darkness that are triyng to conquer the city of Shijuku.
Overall, it is a well animated show with no slow points (in 6 episodes, I am not sure if that is even possible).
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Elfen Lied is centered around the interactions and discrimination between humans and the Diclonius, a mutant species that appears similar to humans but has two cat-ear-like horns and "vectors" which are transparent arms that can pass through air and objects at high speed.
It is pretty dark, and has lots of gore and nudity... and I mean lots.
If you are looking for a story that while it gives off a similar vibe it is less explicit, I would recommend watching Gunslinger Girl.
Gunslinger Girl revolves around the Social Welfare Agency, an institution sponsored by the Italian government. While it says that it aids the rehabilitation of the physically injured, it is actually a military organization specializing in counter-intelligence and counter-terrorism, using its injured patients as tools by giving them cybernetic implants and putting them through a brainwashing process known as "conditioning".
Both Elfen Lied and Gunslinger Girl have 13 episodes.
FLCL is a 6-episode anime about the interactions between Naota Nandaba, a twelve-year-old boy and the eccentric Haruko Haruhara, who arrives in the quiet suburb, drawn by the industrial town houses and the Medical Mechanica building.
Haibane Renmei is about Rakka, a newly hatched Haibane (a being resembling an angel with a halo and charcoal-coloured wings), and other characters in the city of Glie, which is a town surrounded by walls with a single gate through which only the mysterious group the Toga are allowed to enter or exit.
This anime is pretty surreal, and is rumored to be about purgatory.
Also, there is not a single fight scene in this 13-episode anime, as it is entirely character-driven.
Death Note is about Light Yagami, a high school student who discovers a supernatural notebook dropped on Earth by Ryuk, a shinigami ("death god"), that allows him to kill anyone by writing the victim's name in it. The story follows Light's attempt to create and rule a world cleansed of evil by using the notebook to kill criminals, and detective know as L who is trying to track down and arrest him.
This story's theme is on how power corrupts, and absolute power corrupts absolutely.
Side Note: So, you've seen 5 Centimeters Per Second? What did you think of it?