Willow Danielle Rosenberg is a fictional character created for the fantasy television series Buffy the Vampire Slayer (1997-2003). She was developed by Joss Whedon and portrayed throughout the TV series by Alyson Hannigan. Willow plays an integral role within the inner circle of friends--called the Scooby Gang--who support Buffy Summers, a teenager gifted with superhuman powers to defeat vampires, demons, and other evil in the fictional town of Sunnydale. The series begins as Buffy, Willow, and their friend Xander are in 10th grade and Willow is a shy, nerdy girl with little confidence.

The Buffy television series first aired mid-season in March 1997, almost immediately earning positive critical reviews. Willow is presented as a bookish nerd with considerable computer skills, dowdily dressed and easily intimidated by more popular girls in school. She grows faint at the sight of monsters, but quickly forms a friendship with Buffy Summers (Sarah Michelle Gellar) and is revealed to have grown up as friends with Xander (Nicholas Brendon). They are mentored by the school librarian who is also Buffy's Watcher, Rupert Giles (Anthony Stewart Head), who often works closely with Willow in researching the various monsters the group encounters. Joss Whedon found that Hannigan was especially gifted reacting with fear (calling her the "king of pain") and viewers responded strongly when she was placed in danger, needing to be rescued by Buffy. Willow in various predicaments became common in early episodes. However, Willow establishes herself as integral to the group's effectiveness, often willing to break rules by hacking into highly secure computer systems.  In the second season when the characters are in 11th grade, Willow becomes more sure of herself, standing up to the conceited Cordelia Chase (Charisma Carpenter), and approaching Xander, on whom she has had a crush for years, although it is unrequited as Xander is in love with Buffy. Seth Green joined the cast during the second season as Oz, a high school senior who becomes a werewolf, and Willow's primary romantic interest. The show's popularity by early 1998 was evident to the cast members, and Hannigan remarked on her surprise specifically. Willow was noted to be the spirit of the Scooby Gang, and Hannigan attributed Willow's popularity with viewers (she had by May 1998 seven websites devoted to her) to being an underdog who develops confidence and is accepted by Buffy, a strong, popular person in school. Hannigan described her appeal: "Willow is the only reality-based character. She really is what a lot of high-schoolers are like, with that awkwardness and shyness, and all those adolescent feelings."  At the end of the second season, Willow begins to study magic following the murder of the computer teacher and spell caster Jenny Calendar (Robia LaMorte). Willow is able to perform a complicated spell to restore the soul of Angel, a vampire who is also Calendar's murderer and Buffy's boyfriend. During the third season three episodes explore Willow's backstory and foreshadow her development. In "Gingerbread", her home life is made clearer: Sunnydale falls under the spell of a demon who throws the town's adults into a moral panic, and Willow's mother is portrayed as a career-obsessed academic who is unable to communicate with her daughter, eventually trying to burn Willow at the stake for being involved in witchcraft; her father is never featured. In "The Wish" a vengeance demon named Anya (Emma Caulfield) grants Cordelia's wish that Buffy never came to Sunnydale, showing what would happen if it were overrun with vampires. In this alternate reality, Willow is an aggressively bisexual vampire. In a related episode, "Doppelgangland", Willow meets "Vamp Willow", who dresses provocatively and flirts with her.

What is her back story?
Willow's mother is portrayed as a career-obsessed academic who is unable to communicate with her daughter, eventually trying to burn Willow at the stake