Because a Noh play is centered on the protagonist (Shite), the Nohwaki, the musicians and the Noh jester (Kyogenkata) are generically called, "the three key characters (Sanyaku)".
能は、シテ方が中心となって行われるため、ワキ方、囃子方、狂言方を総称して「三役」と呼ぶ。