Maester Jyscal Guado is a side character created by Square Soft for the game Final Fantasy X. He has a small spoken role in the game and is a catalyst character for several plot points. Square literature indicates that he was in his late fifties at his death.

Prior to his death, he was the leader of the Guado nation and is attributed with brining the Yevon religion to that ethnic group. In addition to being known for his leadership, he is also known for his choice of bride. Jyscal married a human woman and their child, Seymour, was the first half Guado child. At several points during the game, there are opportunities to speak to both humans and Guado regarding Seymour, his parentage, and his father. During these conversations, it becomes clear that while the Guado followed Jyscal's leadership as ruler and spiritual advisory, they were not pleased with his decision to marry outside their ethnic group. Both the wife and son were rejected by the guado nation and were eventually sent away into exile.

As a Maester of Yevon, Jyscal appears in chapters of Legendary Guardian when the Council of Maesters meets or when other political situations arise. Additionally, he is featured in Bonds of Love and Braska's Journey in his role as leader of the Guado nation and a somewhat kindred spirit to Lord Braska.