The Slayers
Played by Sarah Michelle Gellar, Buffy Summers is an 18 year old senior at Sunnydale High School. Your typical teenage girl with the one exception of being a slayer. Buffy was once a cheerleader, but had to give it up after the exciting episode, "The Witch", where Amy Madison got her kicked off. She has had relationships with many different guys some including: Ford, Owen, Angel, Scott, and more. Buffy's mother, Joyce Summers (Kristine Sutherland) and father Hank, divorced after Buffy burned down the gym at her old school, causing the move to Sunnydale. In the first season, Buffy's worst enemy was the Master (Brian Thompson), which she defeated in the finale of that season, "Prophecy Girl." In the second season, she had many more encounters with evil, but her main enemies being Spike (James Marsters) and Drusilla (Juliet Landau). Buffy and Angel get close this season and "make a happy", which then makes Angel Angelus and he switches sides on Buffy. A new slayer comes to town, Kendra (Bianca Lawson) causing some confusion. She appears in the episode "What's My Line" pt. 1 and 2. And then again in the finale of season 2, "Becoming" pt. 1 and 2. In "Becoming" Buffy tells her mother she is a slayer, Spike wants to help her kill Angel, she sends Angel to Hell, and leaves Sunnydale on a bus to LA. Currently, in the third season Buffy is back in school (gets away without expulsion), has somewhat of a relationship with Angel, when she unexpectedly frees him from Hell. In the episode, "Helpless" Buffy has to face a strong vamp without her "powers" and survive. This is a ritual that only the watcher is supposed to know about. Seeing Buffy's pain, Giles tells her what is happening. Buffy succeeds in the ritual, but because Giles told her, he becomes fired. A new watcher is sent to Buffy by the name of Wesley Price (who everyone makes fun of!) Although Angel and Buffy went to her prom, they broke up in the episode "The Prom," which is in the third season. In the 4th season, Angel is in LA so Buffy is in a new relationship with Riley Finn. In the episode "This Year's Girl," Faith comes out of her coma and her and Buffy finish what started in the third season finale "Graduation Day."
I don't know where Kendra is really from, just that she had a very unlively childhood. She left her parents, school, friends, and everything else to go train with her watcher. She first appeared in "What's My Line" pt. 1 and 2 suspecting Buffy as a vampire because she was kissing Angel. Buffy then brought Kendra to Giles who explained that Kendra was called when Buffy briefly drowned in "Prophecy Girl." Since Kendra was taught that things like school friends, and family were bad, she was very surprised that Buffy had friends and attended school. She was never introduced to guys and when she met Xander, she went a little gaga. Kendra went back to where she came from in pt. 2 of "What's My Line" and came back in "Becoming" pt. 1 and 2, where Drusilla killed her. Drusilla mesmerized Kendra's mind, then slit her throat with a long fingernail. Buffy was the first to find the body and it was a sad moment for her and everyone else.
Faith, played by Eliza Dushku, doesn't really let people into her life, so the info abotu her is limited. We do, however, find out that her watcher was a female and killed by Kakistos right before Faiths' eyes. This carefree living gal takes slaying not as a job but as the one thing she can do right, and always has fun while doing it. Faith is seductive and gets what she wants. We see this in "The Zeppo" when she gets Xander. Jealous of Buffy and Angel's relationship, she tried to mess it up by trying to turn Angel back to Angelus. When Faith switches sides, she becomes one of the bad guys along with the Mayor and his group. In the episode "Graduation Day" pt.1 Faith shoots Angel with a poisonous arrow. Because the slayer's blood is the only key to the recovery, Buffy goes to Faith to kill her. She succeeds but then Faith falls of a high ledge and onto a truck. She is later seen in a hospital in a deep coma. In the 4th season episode "This Year's Girl" Faith comes out of her coma and is all set to attack Buffy and finish what they started in the 3rd season finale.