Sue Sylvester is our Glee character for this week. The role is being played by Jane Lynch. She is the head coach of the "Cheerios", the cheerleading group of McKinley High. She is also the arch-nemesis of the glee club. She will do everything just to win.
She had tried to destroy the Glee club many times but she was unsuccessful. She allowed Quinn, Brittany and Santana to join glee club to destroy the group but the three girls eventually loved the group. She also made stories between Mercedes and Rachel about the "DIVA" thing that caused them to have a diva showdown but in the end both just enjoyed their performance.
For me, her most noted performance was "Vogue" by Madonna. She sang this together with Kurt and Mercedes in the episode, "The Power Of Madonna" in season 1.
She also had a performance with the entire New Directions with the song "Sing" in Season 2 episode 13: "Comeback".
I'm not sure what else or how worse Sue can do to the glee club members. I hope that she can be kind in the future.