Master Miis are even harder than Expert. These are the ultimate last resort.
List
Wii Party
These are Lucia, Matt, Akira, Pablo, Tyrone, Victor, Eddy, Hiromasa, Sakura. Stephanie, Pierre, George, Yoko, Marisa, Asami, Emma, Steph, Jackie, Takumi, and Alisha.
Wii Party U
Barbara, Yuehua, Na-rea, Rie, Susie, Barry, Faustine, Maximilian, Joana, Jeff, Daisuke, Olga, Jianjun, Maria, Bo-Jia, William, Joost, Clara, Araceli, Sara, Anna , John and Polly