Seymour Guado is a creation of Square Soft, and is a central character to the story line of the game Final Fantasy X. He is, at one point, a playable character.

Seymour, as a motivational participant in the political developments of the guado nation, features in Legendary Guardian and Braska's Journey. He is mentioned by several characters as a result of this fact and is the Summoner that sends Sidoine, wife of Inek, High Priest of Bevelle Temple. His birth and the subsequent political termoil that ensued is also described in the Maechen "white paper" The Church of Yevon: A Brief Developmental History.

Square's official description for Seymour reads:
Male - Age 28 A charismatic leader of the Guado race, Seymour is worshiped and hailed by many for the equal treatment of all citizens of Guado. Born into aristocracy, he inherits the title of Maester of Yevon and becomes the leader of the Guado tribe after the untimely death of his father

Seymour, in addition to having magic spells at his command is also a Summoner, thus he is thrice a "lord" - leader of his people, High priest of the Macalania Temple and Yevon Maester. The tale of his birth as the first "half guado" child, his parent's shocking romance, the political exile of he and his mother, and his triumphant return are all stories that you may hear told by passers by, priests, and guado alike as you travel Spira. It's a long and complex tale that is at the heart of the plot of FFX and, therefore, is also intertwined in LG and Journey.