• English / United States: Saizo
• Japanese / Japan: サイゾー
• Japanese (Romanized) / Japan: Saizo
• Japanese (TL) / Japan: Saizo

Saizo is a high-ranked ninja and the instructor assigned to Sanpei. He had a task for Sanpei and asked him to take a secret document containing ninja techniques that have been taught in their ninja village since olden times and deliver it to their allies.

While Sanpei was attempting to complete his task, Saizo decided to test Sanpei to affirm how much he had grown on his journey. He dressed up as a masked ninja and attempted to steal the secret document. Sanpei though teamed up with Ash Ketchum and Saizo was impressed as he clearly saw that he communicated his thoughts as he faced many difficulties.

After Sanpei safely finished the mission and Saizo revealed himself as the masked ninja, he told Sanpei that he would report back to their elder.