Mina Aino is probably the only one that will ever truely understand Serena considering the likeness of their personalities. Like Serena, Mina is cheerful, but she to is a huge underacheiver. Mina is wrapped in happiness and her main goal of being a Senshi, besides protecting the Princess, is to make sure the world is happy.
Mina likes to goof off a lot. This gets in the way of school and keeps her in detention on a regular basis. Her happiness is pure and her friends love it. Haruka and Michiru despise her happiness, but envy it too. Mina desperately wants to be in a relationship, and she wants her friends to be in one too. Mina and Raye share a relationship that is close to romantic. She and Raye even proclaim, while holding each other, that they don't need men.
Mina wants to be a star one day, wether it be singing her heart out on stage, or being the damsel in distress in a movie. Mina feels that she can do more good famous than not. Mina strives to become a good actor and singer in hopes that one day she'll hit it big.
Mina's relationships with her friends differ from friend to friend. Mina and Raye’s relationship, like previously mentioned, is almost romantic(read StarS 1). They hold each other and care for one another like a couple would do, but with out the physicality of a marriage. Mina consideres Lita as the sister she never had but always wanted. When Mina needs to talk about something, she talks to Lita despite her connection with Serena. Amy is indifferent to Mina. She does care about her, but she doesn't know what to do with her sometimes. Amy is usually Mina's tutor and through her learning Mina found a great friend. Serena is, by far, Mina's best friend, they share everything. Mina also holds a secret, Serena is the dearest thing to her. She even proclaims Serena as her "one and only" to the Starlights. To Mina, there is nothing more precious or pure, and she'd give her life for her.
Sailor Venus is the fourth and last scout to join Sailor Moon. She disguises herself as Princess Serenity. Many people argue the reasons to Venus' disguise: to protect the real princess by drawing the attention from Sailor Moon to herself, to allow Sailor Moon to grow more before the truth was revealed, and many more. We may never know which one but all the reasons are good.
I intentionally failed to say "discovered" in the last passage when talking about Sailor Venus. Sailor Venus was the first scout to be awakened but the last to join Sailor Moon and the Inner Planet Senshi. Most people know but if you don't, Sailor Venus is Sailor V. "Code Name: Sailor V" was Ms. Takeuchi's first Sailor Scout. As "Code Name Sailor V" died and "Sailor Moon" was born, the two stories became inertwined. Even at the beginning of "Sailor Moon" Sailor V was mentioned.
Sailor Venus’ attacks are made with whips bound in love or in beauty. Sailor Venus can also harness some Moon power which makes her almost as strong as Sailor Moon herself. Sailor Venus can also disguise herself like Sailor Moon if needs be. (See Book 8)