Angel
(David Boreanaz)
Angel was born early in the eighteenth century. By 1753 he was living in Galway, as a drunkard and womaniser. There he was made a vampire by Darla, and, as "Angelus", subsequently travelled Europe, leaving a trail of destruction in his wake, more than earning The Master's description of him as "The most vicious creature I ever met."
When Angel first encountered Buffy, it was as a shadowy advisor who warned her about The Master's plan to escape. It wasn't until Angel that he revealed his true form to Buffy. Tending to his wounds after a skirmish with three vampires, Angel tells Buffy he's an orphan, and that vampires killed his parents "a long while ago". He warns that they should not become involved, but they kiss, and Angel morphs into vampire form, and flees. Later Buffy confronts him, her feelings in turmoil, and Angel admits that he killed his family: "for a hundred years I offered an ugly death to everyone I met". Giles cautions Buffy against falling in love with Angel, to no avail, although he does admit that the Slayer falling in love with a vampire is "poetic".
Angel's reign of terror ended when he killed a young gypsy girl offered to him by Darla. The girl's family cursed him by restoring his soul, making it impossible for him to kill again. In Surprise it is revealed that Jenny Calendar was sent to Sunnydale by the gypsy tribe to make sure that Angel never experiences one moment of happiness: if he does, his soul will vanish again, and his evil nature will take control again. Despite Jenny's attentions, Angel and Buffy spend a fateful night together. Angel awakens in pain: he has crossed to the dark side again, and teams up with Spike and Drusilla, crushing Buffy's love in the process.