Darla:
Debut -- Welcome to the Hellmouth (Season 1)
Other first season appearances: The Harvest, Angel
Death -- Angel (Season 1)
Darla is the first character we meet in Welcome to the Hellmouth. She's in the school at night with some guy who used to attend Sunnydale High. They've broken in through a window, and she seems a little nervous. He wants to take her up to the roof of the school, where you can see the whole city. She says she thinks she hears a noise, and he turns around to check. When he says there's no one else in the school but them, she turns around, vamped out, and bites him! So Darla's the first vampire we meet, basically. We see her next at The Bronze, where she's chatting up Jesse. She says her family's been around for a long time, and that he'll probably get to meet them. Darla always dresses in Catholic schoolgirl uniforms, and she looks very sweet when she's wearing her human face.
She leads Jesse into the Mausoleum, and runs into Thomas, who's brought Willow with him. Darla's already bitten Jesse, and it's then that Buffy and Xander show up. Buffy kills Thomas in front of Darla, who can't believe what she's seeing. Luke appears on the scene and Darla runs out to get Xander, Jesse, and Willow, who have escaped.
Biggest Understatement:
"Luke, she's strong!" -- to Luke about Buffy.In The Harvest, we see Darla again. The Master's a little upset with her for having a bite of Jesse since she was supposed to be bringing him for The Master. Darla's just part of the vamp gang in this episode, and she does try to attack Giles in the Bronze, but Willow throws holy water onto her face and she screams and leaves.
Darla's last appearance is in Angel. First she has the honor of killing The Three since they failed to kill Buffy. Then she tells The Master that she knows a way to get Angel to come back into their vamp family.
We learn in this episode that Darla made Angel and that they were involved for several generations. She recalls fondly the days that she and Angel would go on kills, and we learn that she used to wear kimonos a lot.
Darla's come to try to get Angel back into the fold so they can rule in The Master's court together. Darla taunts Angel by saying that he's not human, even though he tries to live above ground, and she urges him to tell Buffy about his curse. Then she sets a plan in motion to get Angel to destroy the Slayer.
Darla snoops in the library and overhears Buffy and Willow talking. She learns that Buffy's going to go home in about 30 minutes, so she goes over to Buffy's house and poses as a tutor. She tells Buffy's mom, Joyce, that she's going to help Buffy study The War of Independence, because her family dates back to then. Once inside, Darla bites Joyce and Angel walks in. She tosses Joyce to Angel and tells him to drink. And since she's timed it perfectly, Buffy walks in and sees Angel holding her mom while he's in vamp mode.
Basically, Darla ends up going to the Bronze to meet Angel and Buffy so she can kill Buffy. She brings guns and does the shooting thing, shooting Angel in the kneecaps. Angel recovers enough to grab a stake and kill Darla with it. The last thing she says is, "Angel."
Also, The Master reveals that Darla was his favorite.
Most Memorable Lines: "Is there anything better than a natural disaster?" -- to Angel, about the good ol' days."You're hurting me. That's good, too." -- to Angel, when she's gotten him angry and he pins her against the wall.
We see Darla as part of a flashback of Angel's life. It's Galway, 1753, and Angel's left a tavern and spotted a beautiful woman alone in an alley. He approaches her and offers to escort her elsewhere. She asks him if he's up to the challenge and he says he's up to any challenge; she tells him she can show him the world, and since he's never been anywhere and probably has no idea what she means, he agrees. Darla tells Angel to close his eyes; as he does, her face undergoes the change and she bites him. Then she cuts herself across the top of her chest and pulls him to her so he can do "the sucking thing." That's all we see of Darla in this episode, but at least now we know what happened.