7. Faith Lehane
"Five by five!" The rogue slayer, Faith (Eliza Dushku) was imbued with slayer powers when Kendra died (Kendra being the slayer who was called when Buffy died before being brought back to life). Her methods were very different to Buffy's. She was rough, ready, far more brash and came to Sunnydale with her then very raw, naive and inexperienced Watcher - Wesley Wyndam-Pryce - whom she took very little notice of. She was tempted to the side of evil by Mayor Wilkins, whom she saw as the Father figure she never had growing up, and became a grave threat to Buffy and her friends. This resulted in her murdering innocent people and fighting against the Scoobies. Ultimately, she would redeem herself twice over - helping Angel in the fight against the Beast and then helping Buffy in her final battle against the First Evil.