After Tasha turns more people and refuses to stop killing, Kate realizes her sister is too far gone and kills Tasha herself. Key Character Moments Supernatural, Season 10, Episode 4: Paper Moon
Kate wants to rehabilitate her sister, while Dean believes they must kill her because she is a monster. [S10E4] Paper Moon
Brit Sheridan as Kate and Emily Tennant as Tasha . After Tasha turns more people and refuses to