what was the idea behind the creation of such a character?
It was created as a need for villain in the series.
Sue Sylvester
On our first call, Kevin said, "You need a villain, Murphy remembered. 'And I said, "You know, you're right." 
what is "the spanish teacher"? It is an episode of the American musical television series "Glee". what is the series about? UNANSWERABLE name a few characters from the episode? Will Schuester, Sue Sylvester, David Martinez, to name a few. who is the second character? It is a fictional character portrayed by actress Jane Lynch
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Sue Sylvester [SEP] Casting and creation
Sue is played by Jane Lynch. The character did not exist when the script for the "Glee" pilot was first submitted to Fox. In an interview with "Entertainment Weekly", Ryan Murphy said that Fox Entertainment president Kevin Reilly was responsible for her creation. On our first call, Kevin said, "You need a villain, Murphy remembered. 'And I said, "You know, you're right." I knew exactly who she is. I said, "Her name is Sue Sylvester. And she is the cheerleading coach. And she may be on horse estrogen. The casting notice described Sue as "the anal, tightly wound, and ruthlessly ambitious leader of the Harrison High cheer leading squad." At the time she was cast as Sue, Lynch was already committed to do a Damon Wayans pilot for ABC.