Kendra was sent to Sunnydale by her watcher, Sam Zabuto because a "dark power is about to rise in Sunnydale". Giles realized that Kendra was called because Buffy had techically died for a minute or so in "prophecy girl".
Kendra turns out to be the complete opposite of Buffy. She follows the rules explicitly. She was taught that school, friends and family would distract her from her calling. She was sent to her watcher when she was young and doesn't even remember her parents. Buffy saw that Kendra's fighting technique was excellent, but she lacked emotion. While fighting, one of the Tarakan assassins rips Kendra's shirt which infuriates her and allows her to wail on the assassin. Kendra ends up going back to her watcher once they believe that Spike and Drusilla are dead.
She comes back in "becoming part 1", because something is brewing again. She brings with her a sword that can be used to defeat Acathla, the demon that Angelus is trying to resurrect. When Buffy goes to confront Angelus she leaves Kendra behind with her friends who are trying to recurse Angelus. She gave Buffy her stake, Mr. Pointy for good luck. Unfortuneately, while Buffy's gone, Drusilla and her minions attack the library. Drusilla hypnotizes Kendra and then slits her throat with her fingernail. Buffy realizes what is going on and rushes to the library, but she's too late. She finds Kendra lying dead on the floor.
Kendra: I am Kendra! De Vampire Slayer!
Buffy: Okay, one more time. You're the who?!
Kendra: I'm de Slayer.
Buffy: Nice cover story. But here's a tip: you might wanna try it on someone who's not the real Slayer.
Kendra: Ya can't stop me! Even if ya kill me, anodder Slayer will be sent to take me place.
Buffy: Could you stop with the Slayer thing? I'm the damn Slayer!
Kendra: Nonsense! Dere is but one, and I am she.
Kendra: Did anyone explain to you what secret identity means?
Buffy: Nope. Must be in the handbook. Right after the chapter on personality removal.
Kendra: De tings you do and have, I was taught, distract from my calling. Friends, school... even family.
Buffy: Even family?
Kendra: My parents, dey sent me to my Watcher when I was very young.
Buffy: How young?
Kendra: I don't remember dem, actually. I've seen pictures. But, uh, dat's how seriously de calling is taken by my people. My modder and fadder gave me to my Watcher because dey believed dat dey were doing de
right ting for me, and for de world.
Buffy: Oh, well, when we were fighting, uh, you're amazing! Your technique, it's flawless, it's, hmm, better than mine.
Kendra: I know.
Buffy: Still, I woulda kicked your butt in the end. And ya know why? No imagination.
Kendra: Really? Ya tink so?
Buffy: Oh, I know so. You're good, but power alone isn't enough. A good fighter needs to know how to improvise, to go with the flow. Uh-uh, seriously, don't get me wrong, y-you really do have potential.
Kendra: Potential? I could wipe de floor wit you right now!
Buffy: That would be anger you're feeling.
Kendra: What?
Buffy: You feel it, right? How the anger gives you fire? A Slayer needs that.
Kendra: Dat's me favrit shirt! Dat's me only shirt!
Kendra: You talk about slaying like it's a job. It's not. It's who you are.
Buffy: Did you get that from your handbook?
Kendra: From you.
Buffy: I guess it's something I really can't fight. I'm a freak.
Kendra: Not de only freak.
Buffy: Not anymore.
Buffy: You know, polite people call before they jump out of the bushes and attack you.
Kendra: Just wanted to test your reflexes.
Buffy: How about testing my face-punching? 'Cause I think you'll find it's improved.
Kendra: I was on my way to your house. Saw you walking. Couldn't help meself.
Buffy: Which begs the question, and don't think I'm not glad to see you, but, why are you here? Oh, wait. No, let me guess. Your watcher informed you dat a very dark power is about to rise in Sunnydale.
Kendra: In case de curse does not succeed, dis is my lucky stake. I have killed many vampires wit it. I call it Mr. Pointy.
Buffy: You named your stake?
Kendra: Yes.
Buffy: Remind me to get you a stuffed animal.
