Anya Jenkins & Andrew Wells
Aud/Anyanka/Anya Christina Emanuella Jenkins ( Emma Caulfield )
Anya is a 1,120 year old former vengeance demon (Anyanka) who specialized in avenging scorned women. After being forcibly stripped of her demonic powers by Giles, the character is forced to re-learn how to be an ordinary human, a journey which is portrayed as both comical (e.g., her fear of rabbits and her love of money) and poignant (e.g. her grief over Joyce's death). Her story is largely focused on her romantic relationship with Xander, and like many characters on the show, she is portrayed as morally ambivalent.
Andrew Wells ( Tom Lenk )
Andrew is a nerd who becomes a foe of Buffy, mainly through peer pressure and bad judgement. He does try to redeem himself throughout season seven. There are several humorous hints that he was gay or at least questioning his sexuality. His character continues to grow and develop after the end of Buffy season seven, as evidenced by his guest appearances on Angel. During Season 8, he resides in Italy being the Watcher of many vampire slayers.
Anya & Andrew
Andrew develops an odd friendship with Anya, who he believes is "the perfect woman", a statement which Anya very much agrees with. Their friendship is made clear in Chosen , where Anya is killed. He lies about Anya's death and tries to heroize her by telling Xander Harris "She was incredible. She died saving my life," (though it's possible that, from his perspective, she did).