Sergio Díaz, also known as Darth Ultor, was a Force-sensitive Male Human Jedi Master and ancient Sith Lord, the primary participant of the CIEDI Chronicles, the Battle of the Hills, founder and Grand Master of the Jedi Order on Earth aside with Jedi Master Alejandro Quintana. He was known in the Old Republic era for carrying the mission of recruiting Force-sensitive people for the Jedi Order on Earth together with Alejandro Quintana and also for his continuous research and learnings on Force knowledge, the dark side of the Force and the light side.