Coach Pi is a Homestar Runner fan character created by MrMenCentral. She was created when MrMenCentral wanted to make Miss Kind, one of his Mr. Men OCs, a Homestar Runner character. Since there were already Coaches A-Z at the time of her creation, he used the name Coach Pi for her.
Domicile: The Coach Castle
Even though MrMenCentral does most of the voices for the Flash versions of his fanstuff, Coach Pi is not voiced by MrMenCentral (neither is Fhqwhgads).