Your favorite character (Mizuno Ami, aka Sailor Mercury) is autistic. This shouldn't even come as a surprise. Ami (or, as I grew up calling her, Amy) was the first fictional character on whom I developed a strong attachment. She debuted in 1992 in the Japanese manga series The Super Dimension Fortress Macross where she was created by Yoshifumi Nishimura. She has since appeared in many other media including anime, video games, and music albums.
According to an interview with Shoko Fujibayashi (the voice of Ami), she had autism spectrum disorder (ASD). Ami suffered from auditory processing disorder (APD), which means that she had trouble processing sounds. She also had problems with social interaction and communication. APD is not uncommon among people with ASD and can also be found in some neurotypical individuals. However...
...there are some details about Ami's behavior that don't quite match up with what is known about ASD. For example, she would often get upset when someone didn't understand what she was saying. This isn't typical of people with ASD who usually try very hard to communicate their needs and desires. Also, she would sometimes engage in self-injurious behaviors such as hitting herself in the face with objects or rubbing her head against walls. Some have suggested that these behaviors were part of a method used by Ami to cope with her feelings of isolation.
Mashiro Shiina is autistic. While it is never formally stated, Mashiro shows many of the characteristics associated with autism. She speaks in a monotonous tone, and her eyes appear to be blank. In some ways, she appears robotic, which is a description that many of us have heard about our personalities.
It is revealed in the fourth episode of the anime that Mashiro's mother died when she was young, causing Mashiro's father to withdraw from society. He built a robot named Gafgarion to protect him from people like him.
Gafgarion has a brain similar to humans', but its casing is made of metal instead of flesh and bone. It has two main modes of operation: one is where it will try to convince people not to harm Mashiro's father, the other is where it fights against enemies. Gafgarion has been known to lose several battles before it finally collapses from exhaustion. However, it always repairs itself before continuing on its mission.
Mashiro was once told by her father that she would one day become a great hero, and so she strives to be the best robot she can be. Despite this, she still has days where she feels sad and alone because nobody knows she exists.
In conclusion, yes, Mashiro Shiina does have autism.
The exploits of the title protagonist, Sailor Moon, her boyfriend, Tuxedo Mask, and her guardians, Sailors Mercury, Mars, Jupiter, and Venus, are chronicled throughout the series. They are subsequently joined by Chibiusa (the future daughter of Sailor Moon and Tuxedo Mask) and four additional guardians: Sailors Pluto, Uranus, Neptune, and Saturn. The seventh Sailor Guardian is Sailor V, the final guardian before the apocalypse. She is a child who grows up to be the hero Princess Victory.
Each sailor guardian has their own powers and abilities. For example, Sailor Mars can fire energy beams from her lance, while Sailor Jupiter can control the weather. Some of them have relationships with other characters in the series; for example, Sailor Venus is often seen together with Prince Planet.
Sailor Moon was born on a summer night when everyone else in the world was asleep. She was given a mission by the goddess Luna to protect the universe from evil. Before she could fulfill this mission, however, an alien race known as the Black Stars attacked Earth. Only Moon's cry for help during these times of danger caused her to be born again as a child named Chibiusa. This allowed Chibiusa to take on her role as Sailor Moon while Moon stayed behind on Earth until she grew up.
After defeating the Black Stars, Sailor Moon traveled around the world protecting people from evil. However, since she was only human, she needed help guarding against evil monsters.