Madison (Anime Series)

Madison is a character from Supernatural The Animation.

Overview
Madison was the assitant of Mulligan, a lawyer working at the DA's office. One night, Mulligan is killed by what appears to be a wild dog, though Sam and Dean Winchester correctly deduce that it's a werewolf attack.

During interrogation, Madison reveals she is having problems with her ex-boyfriend, who often suspected there was something between her and Mulligan. Sam, having grown attached to her due to similarities between Madison and Jessica, promises to protect Madison whatever the cost.

Problems arise when Madison herself transforms into a werewolf and kills Kurt. Dean wants to kill her, but Sam chooses to find an alternative. They agree to hunt down the one responsible for biting Madison, but despite killing the werewolf, Madison remains unchanged.

Madison desperately wants to kill herself out of grief, but Sam stops her every time. Eventually, the brothers are forced to hunt her down when she goes to attack Dean. Sam is the one to shoot her.

Trivia

 * Madison is based on Madison (aka "Maddie) from the original TV series.
 * Madison has shorter hair and never becomes sexually involved with Sam in the Anime series. She also never voluntarily asks Sam to kill her, but ends up forcing his hand by attacking him.