Alyson Hannigan 1989, her first regular role on a TV series came when she was cast in the short-lived ABC sitcom "Free Spirit". As a teenager, Hannigan babysat for the children of her future "How I Met Your Mother" costar, Bob Saget. In 1997, Hannigan was cast to play Willow Rosenberg, Buffy Summers' best friend, on the television series "Buffy the Vampire Slayer". The show became a success, and Hannigan gained recognition, subsequently appearing in several films aimed at teenaged audiences, including "American Pie" (1999), "Boys and Girls" (2000), "American Pie 2" (2001), and "American Wedding" (2003). She also had a guest
Satsu (Buffy the Vampire Slayer) on Earth. During this time, she is revealed to be working for the United States Armed Forces, and in a relationship with an undisclosed partner. Satsu was one of several original characters invented by series creator Joss Whedon for "Buffy the Vampire Slayer Season Eight", a comic book continuation of "Buffy the Vampire Slayer". Whedon described the concept for Satsu's relationship with Buffy as "evolv[ing] naturally" during the development of "Buffy the Vampire Slayer Season Eight". He viewed the story arc as "an opportunity for drama and character exploration" set up over the course of the comics, which had established