Iliaster

Yliaster (Illiaster in the English dub), literally meaning the first chaos in the matter of all things, is the secret society of Star Guardians who are said to bring peace to the world and serve as the central antagonists of Yu-Gi-Oh! 5D's.

According to Rex Goodwin, Yliaster started approximately 3,000 years ago in the Andes in South America and all who have sworn loyalty to Yliaster govern every aspect controlling society. Although Goodwin had stated that Yliaster's agenda is for the benefit of the human race, skeptics such as Sayer believe that Yliaster plans to use the Crimson Dragon for world domination.

That would be substantiated when the oldest Emperor Jakob asserts that the organization was founded by their God, with the objective of "correcting" history when humans puts it on the wrong path. He further states that they have done so many times throughout the centuries. Seeing as they are willing to destroy entire cities in pursuit of their agenda, it would appear the organization is not concerned about individual lives to fulfill what they perceive as the "greater good".

Apparently two different versions of Yliaster exist in the series. The Yliaster of season 1 was a sub-faction of the main cabal that were assigned the mission of discovering the identities of the Signers and ensuring they are prepared to defeat their enemies the Dark Signers. The Yliaster of season 2 was involved in the World Racing Grand Prix and plotted to change the future of New Domino City by destroying it. The Three Pure Nobles confirm it was their directive to manipulate Roman Goodwin to cause Zero Reverse making them indirectly responsible for the creation of the Dark Signers, therefore they temporarily modified their agenda to eliminating the menace of the Dark Signers before they destroyed the planet they intend to protect from the catastrophe of Synchro Summoning and Ener-D.

First season
Rex Goodwin leads the group of Yliaster in New Domino City during the first season in the form of Sector Security. They are the ones responsible for organizing the Fortune Cup and use it as a setup in order to expose and gather all of the Signers, in which to help them fulfill their roles as the heroes against their counterparts, the Dark Signers. They also share some connection with Professor Fudo, who entrusted Rex with 3 of the Signer Dragon cards that Yusei, Jack, and Akiza now possess.



It has been revealed that, 17 years ago, a mysterious individual belonging to this group appeared to Goodwin's older brother, Roman Goodwin. The man told Roman that the Ener-D research project had to be continued even if it meant getting rid of Professor Fudo. Also, he told Roman to look into the light of the Ener-D system so that the then long ago chosen Signer could witness the battle between the Crimson Dragon and the Earthbound Immortals. The mysterious individual then simply vanishes within a sandstorm.

Second season
In this new season, beginning from episode 65, three mysterious people arrive at the crash site of a strange meteor, where they are questioned by Lazar; Lester informs him that they are his new bosses, apparently all sharing the title of Director of Sector Security.

Their goals were unknown at first, however, with the appearance of the female Turbo Duelist, Sherry LeBlanc, a part of their purpose had been revealed. For one matter, she solemnly believes that Yliaster is responsible for the murder of her parents.

On the other hand, she reveals that Yliaster is seemingly involved with the prestigious tournament known as the World Racing Grand Prix. According to the Three Pure Nobles, they are using the tournament as well as the Signers in order to complete the Grand Design.

Trivia

 * After the four remaining humans, Z-one, Aporia, Antinomy, and Paradox, transformed their bodies into machines, they have all been left-handed duelists. In Antinomy's flashback, viewers can see that he and Z-one, in the form of Yusei, were right-handed duelists. Also, when Aporia has his own flashback while dueling Z-one, he is shown to be right-handed as well.


 * Although Jakob claims Yliaster have existed since Ancient times, this is proven wrong in later episodes such as 135 and 144, in which it is shown that the organization was merely made up of a few survivors of the original future.