Sailor Moon
Usagi Tsukino
Sailor Moon is the leader of the Sailor Guardians and when her and the others are fully awakened, she is remembered as the Moon Princess Serenity. She is the Champion of Love and Justice and first appears in Volume 1 of the manga and Act 1 of Sailor Moon Crystal.
Sailor Moon transforms with a brooch that a cat named Luna have her. She calls out the magical words: "Moon Prism Power Make Up!" and has a special attack during her first fight. She cries which then amplifies the sound waves from the hair shields in her odangos (hair buns). Right after crying, she learns that she has an actual attack called "Moon Tiara Boomerang" which she throws her tiara at the enemy basically slicing them in half.
During Act 4, Sailor Moon realizes she can no longer user her tiara attack and instead uses her new tiara to reflect th emoon at the youmas. By Act 6, she is given the Moon Stick and with Tuxedo Mask's help is able to heal everyone by shouting "Moon Healing Escalation." She can also attack the youmas with this attack.
Sailor Moon's mission throughout the first ??8?? acts is to find the Princess and protect the "Legendary Silver Crystal". Little does Sailor Moon know, she is the Princess and she holds this crystal of immense power.
<<<More to come as the series advances>>>
So far nothing is known in Sailor Moon Crystal about Princess Serenity. According to the manga she fell in love with Prince Endymion which was forbidden. She was from the Moon and he was from Earth. A war broke out in the old Moon Kingdom, destroying the kingdom and forcing Queen Serenity to sacrifice herself to send her daughter, the cats, the guardians, and Prince Endymion to Earth to be reborn. Princess Serenity carries the Legendary Silver Crystal within her tears in the manga - hopefully this stays true in Sailor Moon Crystal since it shows the absolute love and devotion she has towards her prince.
In Act 8, Sailor V appears claiming that she is Princess Serenity, but Sailor Moon/Usagi feels like she is holding back something very important from her and the others.
<<<More to come as the series advances>>>
Princess Serenity
Usagi Tsukino is the alter ego of Sailor Moon. In her sailor suit and out of it, she is still a crybaby. She's is 14 years old in Junior High and wears her hair up in two pigtails with buns, or odangos. Usagi runs into a black cat with a crescent moon on it's forehead who she soon learns is named Luna. Usagi also learns from Luna that she is a Sailor Guardian named Sailor Moon. She also has weird dreams that seem like a distant memory, but she can't seem to put her finger on it.
As the story progresses, Usagi meets her fellow Sailor Guardians who become her new best friends: Ami Mizuno, Rei Hino, Makoto Kino, and Minako Aino; who through Minako, meets a white cat like Luna whose name is Artemis. Usagi is the one who brings all the girls out of the shells they grew up in. She gets Ami out from behind her books, gets Rei away from the temple and realize that people actually do like her, and shows Makoto (or Mako-chan as she calls her) that she isn't a scary tall person but is actually a very kind and loving person. Usagi even brings Minako to realize that friendship and leadership can come hand in hand.
Usagi also meets a high school student named Mamoru Chiba who at first she dislikes because he is always teasing her, but there is an undeniable attraction between the two. This attraction becomes stronger when they realize each other's alter egos.
Usagi grows throughout the series. She's still the crybaby, but becomes more mature and stronger.
<<<More to come as the series advances>>>