Sartorius, known as Takuma Saiou (斎王琢磨, Saiō Takuma?) in the original Japanese language version, is a fictional character in the Yu-Gi-Oh! GX anime series. His name is meant to be a pun in English, as "satori" denotes a "spiritual awakening". In the English version, Sartorius is voiced by Maddie Blaustein, while Takehito Koyasu (older) and Mayumi Yusa (younger) take the role in the Japanese version.
A fortune-teller with dual personalities under the influence of an alien force, Sartorius serves as the main antagonist of the series' second season, poised to remake the world in the image most befitting the extraterrestrial radiance within him.