People say that the anime gives the senshi more personality - I disagree. The anime exaggerated their personalities and left out really important information related to their backgrounds, like how Usagi is the incarnation of the Moon Goddess Selene, or how Rei was once in love with a man she wished to marry.............instead the anime turned our mature and spiritual Rei into a girl who went ga-ga over men like Mamoru, chasing him around, which is very unlike Rei of the manga.

Personality
The anime and dub portrays Rei negatively, making her look like a mean, hot-tempered, impatient and overly sarcastic woman. She's portrayed as show-offbrash and makes quick decisions without thinking it through as Ami would. It also greatly exaggerates her "fights" with Usagi - fights which never existed in the manga.

In the manga, Rei's character is much more spiritual, calm, and she is not so easily angered, in fact, I cannot figure out WHY the animators had Usagi and Rei fighting at all - it hardly happened at ALL in the manga. She's not even that crazy about men in the manga - she distrusts them because of how her own father isn't around for her but she does have a past love interest in this present life (to be explained below and more in depth in the Love Life section.

Relations to Others
Rei was at first a more withdrawn sort, a loner. This is true in both anime and manga. Rei only began to open up and be friendly to others when she became a Sailor Senshi. With Usagi and the other soldiers, she was given a family and a friendship she didn't have before and this helped her to be more sociable. Manga Volume 4: Act 14 has students passing Rei in the hallway commenting on how Rei is a lot more easier to talk to these days. Before that, the students called her spooky but an inspiration. They looked up to her because of her beauty and strange powers but did not feel they would be friends with the girl.

The reason most likely why she did not have any friends is given in Manga Volume 11 - a special birthday volume about Rei, in which she says: "I have no friends," she says. "And I don't want to make any. You can't have faith in people. I believed in dad. Mom always looked lonely... Mom was a slender person... But in dad's mind, there was nothing besides politics. Mom's weak body was dying alone. In the end, you can only depend on yourself, I think. So I don't want to marry, either." She said this to a man name Kaidou who it was later revealed that Rei, herself, wished to marry and was in love with.

Family
Rei's mother's body was weak, and after she passed away, Rei became a parishioner at the Hikawa Shrine with her grandfather on her mother's side - Manga Vol. 3: Act 14. Since her mother died, Rei didn't get along with her father and that is when she came to the shrine (Manga Vol 11: Casablancas)

Her father's a member of the political world - a member of the Liberal Democratic Party - a party that actually DOES exist in Japan.

Love Life
As beautiful as Rei is, and as many males as she attracts, there was only one man she ever fell in love with and had her heart broken by, read about it in the Love Life section. It should be known though that men are ALWAYS paying attention to Rei in the manga, giving her flowers, buying her drinks - she's very popular with men but part of that popularity is not based soley on her beauty but on the fact that she doesn't chase men around, that she dodn't even show any interest in men. She has made it clear, repeatedly, that she does not like boys. Only 2 men in the manga have captured Rei's romantic interests and that was Chief Kotono - the head of the Supernatural Phenomena group at the T*A Private Girl's School Academy and Kaidou - her father's assistant - to be explained in the Love Life Section

Rei's Dream
Rei has certain principles she lives by such as not looking back on the past, and not wasting money at the shrine, and not falling into silly pursuits such as finding a man with a lot of money to marry so that a woman may live out her life in comfort. Rei is a hardworking woman and dreams of becoming the Head Priestess at the Hikawa Shrine but we learn in Manga Volume 12: Act 36, when she recovers her memory of being Princess of Mars and recalls that she pledged her chastity to Princess Selenity and that she has a greater purpose, a more important dream - she is the "Soldier of Flames", a sworn protector of the Princess Selenity, and that comes before all else in her life and is the goal and dream she was searching for and finally found in that manga act.