One element of Grand iral Thrawn's story from Star Wars' Legends universe, primarily crafted by Timothy Zahn.

Before Disney's acquisition of Lucasfilm, the Star Wars franchise had a vast Extended Universe. The EU has since been dubbed Legends, meaning none of those stories are canon to the Heir to the Empire. Although a version of this is being adapted into Star Wars canon, several elements are being left in the Legends timeline, with a specific one having a few reasons as to why.

What Are Ysalamiri? Grand iral Thrawn's Force-Impeding Lizards Explained

Legends Introduced A Way For Thrawn To Combat The Jedi

Firstly, it is worth exploring what this Legends concept actually is: the ysalamiri. In Zahn's Heir to the Empire trilogy, Thrawn was shown to find a race of lizards called the ysalamiri, which possessed an important ability that could negate the effects of the Force. These lizards produced a natural bubble around themselves which drastically reduced one's ability to manipulate the Force. Given that the Force exists within and around every living creature, the ysalamiri did not remove it completely, yet stripped away the power for someone to use it. For Star Wars' villains, this was a game-changer.

With Thrawn trying to reinstate the Empire in the New Republic timeline of Star Wars, then in Legends, he was facing off against Force-sensitives such as Luke Skywalker, Leia Organa, and Mara Jade. As a result, the ysalamiri became integral weapons in the Grand iral's arsenal. Thrawn would create harnesses to allow him and his allies to negate the Force abilities of his enemies, and even his allies, in the case of the mad clone Jedi Joruus C'boath.

Why George Lucas Likely Didn't Like Ysalamiri

The Creator Of Star Wars Was Not A Fan Of The Creatures

As alluded to earlier, there are several reasons why the ysalamiri will not be included in Star Wars canon's adaptation of Heir to the Empire. Chief among these reasons is simply that Star Wars' creator, George Lucas, did not like the concept of the ysalamiri. According to Lucas' protégé, Dave Filoni, in an interview for Star Wars Rebels which first introduced Thrawn back into canon, the two filmmakers once shared a dislike for the ysalamiri.

Filoni begins commenting on the ysalamiri at 43:20 in the video below.

As proven in a thread by X flamryn, Timothy Zahn was aware of this. Zahn recently appeared at a convention, at which he shared that one of the few notes Lucas had on his original book series was that he did not agree with the ysalamiri. The reason for this is also explained by Filoni in the aforementioned Rebels , with Lucas apparently stating that, because the ysalamiri are alive and the Force exists within all living beings, they should not possess the ability to negate the mystical energy field in any way. Therefore, Filoni left them as an element of non-canon Legends.

Why The New Canon Thrawn Doesn't Need Ysalamiri (He's Got Something Better)

Thrawn Has More Tricks Up His Sleeve

Beyond Lucas' dislike for the ysalamiri and Filoni's dedication to conveying the former's vision in Star Wars, there is another reason why Thrawn will not have the Force-repelling creatures in canon. This reason was established in Ahsoka season 1's ending, where it was revealed that Thrawn had allied himself with three immensely powerful Nightsister witches while stranded in another galaxy. These Nightsisters returned with him to the main Star Wars galaxy, giving him another weapon to use against the New Republic's defenders.

After all, Nightsister magik has been shown to be a way to combat the Force and other weapons of the Jedi in Star Wars canon. Even in Ahsoka, a Nightsister-infused blade used by Morgan Elsbeth kept the titular character busy while Thrawn escaped Peridea. If the Nightsisters stay loyal to Thrawn in Star Wars shows, he will not need the ysalamiri after all and will have other means with which to combat the Jedi.