Formally the vengeance demon-also known as the Patron Saint of Scorned Women-Anya (or Anyanka) has recently seen a lot of life changes in her 1124 years. She was first cursed by the demon D'Hoffryn for practicing vengeance spells on men. As the story goes, Anya first entered Sunnydale to grant a wish with her magic necklace to Cordelia. Rather than wish something bad to happen to Xander, Cordy wished that Buffy had never moved to Sunnydale and a horrible alternate reality was created. Luckily, Giles destroyed the powerful amulet and Anya was transformed into a regular kid at Sunnydale High. The evil D'Hoffryn refused to change her back and she was left not old enough to buy beer and not bright enough to pass math.
During college, Anya returned to seduce Xander so that she could get him out of her mind. However, she ended up falling for him and the two have been extremely sexually active ever since. Anya has been accepted as a primary member of the Slayerettes and it seems as if everyone is letting bygones be bygones.
Although Anya has gotten in touch with her human side, she stills shows her arrogance and demon-nature by butting into conversations and biting into Xander (literally). With Giles returning to England to cope with the death of Buffy, Anya officially becomes the top dog at the Magic Box.