Serena or Usagi Tsukino is the main character and the moon princess in the series "Sailor Moon". She was an average teenage girl living in 20th century Tokyo,Japan until she met Luna from the Moon Kindgom. She transforms into the hero of justice, Sailor Moon to defeat any threatening forces.
Usagi Tsukino ("Serena Tsukino" in the 1990's U.S. dub and "Bunny" in the Manga) began as a typical teenage girl. She's typically characterized as childish, a klutz, crybaby, and a dunce. Those characteristics are balanced by her more positive qualities: her unfailing loyalty, pure heart, and love for all her friends. As the series progresses, she becomes more mature.
One day, she rescued a stray cat (named Luna) from being attacked by a group of boys. The cat later reappeared in her bedroom and revealed to her that she was Sailor Moon. Her first duty was to protect the Earth from the evil Negaverse (also known as the Dark Kingdom) and find the Moon Princess. She eventually met and helped to awaken more senshi to help her fight. She is deemed the leader of the Sailor Senshi after obtaining the Moon Stick and was discovered that she was the Moon Princess much later onwards.
She is in a romantic relationship Mamoru Chiba (Darien) Chiba who also has alternate identities (Tuxedo Kamen, Moonlight Knight, Prince Endymion). The two initially were at odds with another. Mamoru was known for relentlessly teasing Usagi and calling her a "bun head." Much later, when she and Mamoru were in a battle against Zoisite and Kunzite, Usagi was forced to reveal herself as Sailor Moon in order to save herself and Mamoru from being killed. Upon regaining her memories as Princess Serenity, she remembers that Mamoru was Prince Endymion of Earth and that they were lovers during the Silver Millennium.
Sailor Moon was created by Naoko Takeuchi , along with the franchise as a whole as well as the other characters in the series. Various Directors and Producers did several spin-offs and various manga and anime productions of the original story.
Usagi is shown to always have a constant bravery/spark within her, and she doesn't change much morally throughout the series/volumes.
Serena's Hobbies include eating, playing video games, reading manga and picking on Rei (Raye). Interestingly enough, Serena is a Big Fan of Sailor V, whom she later becomes teammates and good friends with. Her weaknesses are thunderstorms and visiting dentists.