Rei is a strong-willed, independent girl, who lives with her grandpa at Cherry Hill Temple where she's training to be a priestess. She attends T*A Private Girls' Academy, where she is treated like a Princess. Rei was born with a sensitivity to the Spiritual World, she often senses danger is in the air, one might say she's psychic. She's very dedicated to her causes, and she is very important to the team in finding the truth about enemies with her fire readings. She is constantly bickering with Usagi, because she is extremly impatient with her clumsiness. That is probably due to the fact she attends a school for rich students and just doesn't have the patience with laziness. However, it's not that she doesn't like Usagi, in fact they are probably the closest, she does what she does to help Usagi....and it shows. As a Sailor Scout, Sailor Mars is extremly aggressive and doesn't hesitate to attack, many of her attacks she knew before even becoming a Scout, because they're attacks that deal with her religion. She also tends to be the first to attack in every fight scene.

Mars Power!
Rei says this to turn into Sailor Mars.
Mars Star Power!
Rei says this to turn into Sailor Mars, later in the series.
Mars Fire Ignite
This is Sailor Mars' main attack, she puts her hands together, and when she says these words, a stream of fire forms that she can control.
Mars Fire-Bird Strike
When Sailor Mars says this, she can create a bird made of fire which can fly around and help destroy her enemies.
Mars Celestial Fire Surround
By far her neatest attack. Sailor Mars says this and forms several rings of fire which can be directed at anyone she wants.
Mars Fireballs Charge
In this attack Sailor Mars (or Rei) holds up a special magic parchment, when she says those words and throws the parchment at a monster or person, that monster/person is stunned.