Iliaster

Yliaster, literally meaning the first chaos in the matter of all things, is the group of Star Guardians who are said to bring peace to the world and serve as the main antagonists of Yu-Gi-Oh! 5D's.

According to Rex Goodwin, Yliaster started roughly 3,000 years ago in the Andes in South America and all who have sworn loyalty to Yliaster govern all things controlling society. Although Goodwin had stated that Yliaster's goals are for the good of mankind, skeptics such as Sayer believe that Yliaster plans to use the Crimson Dragon for world domination.

That would proven that Jakob claims that the organization was created by their God, with the goal of "correcting" history when humanity 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 whole cities in pursuit of this goal, it would appear that they care very little about individual lives to achieve what they believe is the greater "good".

There are apperently two different versions of Yliaster in the series. The Yliaster of season 1 was involved in locating the Signers and making sure they are strong enough to defeat 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. Apparently, It was the season 2 Yliaster who were the ones using Roman Goodwin to cause Zero Reverse, and for being indirectly responsible for the creation of the Dark Signers, therefore maybe they temporally changed their plans into stopping the Dark Signers before they destroy the world they came to save in first place.

First season
Rex Goodwin leads the group 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 Yu-Gi-Oh! 5D's - Episode 065, 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.

Members
Season 1:
 * Rex Goodwin - (former leader, deceased)
 * Lazar - (second in command, defected)
 * Greiger - (English dub, defected)
 * Gill Randsborg - (English dub)
 * Shira - (English dub)
 * Professor Frank - (English dub, incapacitated)
 * Commander Koda - (English dub)

Season 2:
 * Z-ONE - (creator and leader, deceased)
 * Aporia (true form of the Three Emperors, deceased)
 * Jakob (Three Emperors - leader)
 * Lester (Three Emperors - self-appointed sub-leader)
 * Primo (Three Emperors)


 * Antinomy (After episode 145, deceased)
 * Paradox (deceased)
 * Sherry LeBlanc (After episode 117, defected after episode 140)
 * Clark Smith (President of Momentum Express Development Organization and benefactor, ceased from existence)

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.