Kendra the Vampire Slayer:
Debut -- What's My Line, Part 1 (Season 2)
Death -- Becoming, Part 1 (Season 2)
When we first see Kendra in WML part 1, we have no idea who she is. Since we know that the Order of Turaka has been called in by Dru, we suspect that she's one of the assassins who's been hired to kill Buffy. This explanation is especially feasible since we see Kendra getting off of a plane and have been led to believe that she's violent.
The next time we see her, she's scoping out the ice rink where Angel and Buffy are embracing. She sees that Angel is a vampire and that Buffy's smooching him. Kendra resurfaces towards the end of the show...she attacks Angel in a bar and tries to stake him. He has no idea who she is either, but she locks him inside a cage, glances over to the window, and tells hims that it's "eastern exposure." Meanwhile, a noise wakes up Buffy, who's been resting at Angel's place. She sees Kendra is ready to attack her, and she assumes that Kendra is another assassin. The two fight and seem evenly matched. At the end of the episode, it's revealed that: "I am Ken-dra, the Vampire Slayer."
WML Part 2 opens with Kendra and Buffy holding their fighting positions. Buffy's incredulous to find out that Kendra is also a slayer. Slayer lore/procedure dictates that when one slayer dies, the next one is called. Since Buffy was dead for a few minutes in Prophecy Girl, it's plausible that Kendra could be called or activated as the next slayer. It should be noted that this -- two slayers alive at the same time -- was unprecedented.
As the episode goes on, we learn more about Kendra and how her slayer training has differed from Buffy's. Kendra began training at an early age, was taken from her family to fulfill her "sacred duty" and doesn't attend school. She's got no outside interests and is completely focused on her slayer training. Dumb-struck around boys and not too wise in some areas that seem to be common knowledge, Kendra's a perfect foil for Buffy, who's had doubts about her sacred duty since Day 1. Kendra aids Buffy in coming to terms with who she is, and even though I didn't like Kendra at first --can you blame me? That accent was god-awful...-- I was a little sorry to see her leave at the end of the episode. I'm betting she'll be back at some point in the future....
Most Amusing Line:
"No wonder y'died." -- in response to Buffy's line that she does things her way.
Becoming, Part 1 marks Kendra's return to Sunnydale. Her watcher has sent her because again, "a very dark power" is supposed to rise in Sunnydale. She appears in the bushes outside; Buffy's patrolling and senses someone, Kendra pops out, to test her reflexes.
When Kendra learns that Angel's gone evil, she believes that he should be "eliminated" -- she doesn't think they should try to curse him again. When Buffy leaves to go meet'n'kill Angel, Kendra stays behind in the library to keep the gang from being hurt. She gives Buffy her lucky stake, Mr. Pointy, and the chicks bond over that. Unfortunately, Buffy's walked into a trap; namely, the vamps went to the library, and Kendra is defenseless against Dru's hypnotic stare. Drusilla uses her nails to slash Kendra's throat. When Buffy returns to the library, she finds Kendra dead on the floor.
What's troublesome is that I really liked Kendra, a good foil for Buffy, and someone who understood her. It also seemed that she'd loosened up some since we last saw her, and that could be due to Buffy's influence on her from WML part 2. It's too bad she's out of the picture now. Maybe the next activated slayer will be good, though...
Story Arc: Buffy vs. Kendra