Minako Aino
Minako goes to a different junior high school from the other Inner Senshi, but in SailorStars, she attends Juuban High School with them. Her guardian cat is Artemis. She's like Usagi--well, they could be twins. They look almost exactly alike, except that her hair color is a shade different, and they have many moments throughout SM when they do exactly the same things. For example, in the first season, the skating episode, when they convince the others to go skating with them. Also when they stalk Haruka in S, for most of the episode they copy each other...
Minako was the first Sailor Senshi, becoming Sailor V after meeting Artemis. She fought villains there as V, and she was friends with Alan and Katarina, a police officer, while living in England. However, she fell in love with Alan, but both Alan and Katarina thought of her as only a child, and they fell in love with each other. When V and Katarina were investigating a warehouse, a grenade exploded inside, and Katarina thought Minako was killed. It was then as V watched Katarina and Alan embrace that she realized they were in love, and so she left, leaving them to think her dead. She returned to Japan and became Sailor Venus, joining the rest of the Inner Senshi.
In the Anime, Venus's role as the leader of the Inner Senshi is a little less defined than in the Manga, and at times Mars looks like more of the leader. Strangely enough, Minako in the first season is extremely mature; the episode about her past, episode 42, reveals the complexities of her life while as V in England. Somewhere between SM and SMR, Minako apparently gets a ditz attack because after the first season, she shows practically no real maturity as she did before, when Usagi tells the others that "Minako is the most mature out of all of us".