The human birth name of the vengeance demon Anyanka is Aud.
Aud was a human woman living in ninth-century Scandinavia. Around 880, after discovering that her Viking lover Olaf had been unfaithful, she transformed him into a troll. This act of revenge attracted the attention of the demon D'Hoffryn, who offered to make her a vengeance demon.
As a demon, Aud took the name Anyanka and became the “Patron Saint of Scorned Women,” granting wishes that punished men who had wronged women. She eventually lost her powers and was forced to live as a human in Sunnydale, where she adopted the name Anya Jenkins.
A common mix-up is treating Anyanka or Anya as her original name. Those are later identities; Aud is the character’s human birth name. Emma Caulfield played her throughout Buffy the Vampire Slayer.