2022 UPDATE: As of October 26, 2022, Yaddle appeared in Tales of the Jedi season one and the character will go no further. However, like any character in Star Wars, Lucasfilm can always go back in the timeline to tell more stories (like The High Republic) so, treat this post as additional backstory as this question is officially answered.
Yoda was introduced in The Empire Strikes Back in 1980 and became another pop culture contribution from Star Wars, like Darth Vader, the Stormtrooper, and the Millennium Falcon. His line “Do or do not, there is no try” is one of the most quoted lines from the Star Wars franchise.
So it was no surprise that when the Prequel Trilogy came to theaters with the release of The Phantom Menace in 1999, Yoda was present on the Jedi Council. What was less than expected was ANOTHER Yoda species (because that is still a mystery) to appear. Yet there she was, on the Jedi Council when Qui-Gon tells them about Anakin Skywalker and then declines to join. Like most female characters in the Prequels, she had no dialogue and was absent in Attack of the Clones and Revenge of the Sith. Lucasfilm later confirmed that Yaddle was no longer on the Jedi Council post The Phantom Menace. Although, her lack of appearance in all seven seasons of The Clone Wars indicates that she was also not a part of the Order. So what happened to Yaddle who, at the time, was the only other species like Yoda introduced to canon, and how could Lucasfilm just Judy Winslow her out of existence?
Well, Yaddle was never supposed to exist in the first place. Concept artist Iain McCaig created her while he was working on sketches for a younger Yoda for the Prequels. Maybe the puppet was so far into production when they decided not to use it for Yoda and, instead of letting a good puppet go to waste, popped a wig on it and called her Yaddle. If so, Yaddle was never supposed to exist in the first place. But stranger things have happened, and beloved characters have come from weirder beginnings (see Quinlan Vos).
Where She Might Have Gone?
First, let us entertain the idea that she stayed with the Jedi Order and, for whatever reason, stepped down from the Council (replaced by Shaak Ti). The High Republic novel, Out of the Shadows, hints at why she might have forfeited her seat on the Jedi Council. In the book, Jedi Knight Vernestra Rhow runs into the older Jedi Master at the temple. When Rhow wonders why Yaddle has returned so early from sabbatical, Yaddle responds that she missed her time with the Younglings. During the High Republic, Yoda is also mainly working with Padawans and Younglings. He even continues this tradition in The Clone Wars, while also serving on the Jedi Council so one could do both. But perhaps Yaddle chose to prioritize the next generation of Jedi.
If she did stay with the Order, then she could have been another victim of Order 66. The only time that she has appeared in canon is via a vision of Vader in “Darth Vader #25 (2018).” In Darth Vader’s vision, he sees many Jedi whom he has either killed, will kill, or have already died from other causes. Quinlan Vos and Yaddle are the only two Jedi whose fates are unknown at the moment. Vader does kill all the Jedi in his vision (including Yoda) but, for Yaddle, this might be more wishful thinking than what occurred.
Perhaps it is my Yoda bias, but I do not think Darth Vader could defeat a younger and sprier version of Yoda. Also, we have now met three of the same species, and the third one (Grogu) also survived Order 66. That species has favorable odds when it comes to Order 66 and staying hidden from the Empire. Per the Star Wars Character Encyclopedia, Yaddle also possessed the power of morichro, a skill that can slow an opponent’s bodily functions enough to kill. Yeah, she’s not dead.
Will She Show Back Up Again?
References to Yaddle have been made enough times within canon material that it feels like she will return. It started with that Darth Vader comic appearance and then graduated to Star Wars Jedi: Fallen Order. In the story, the Latero pilot Greez is excited with the possibility that Jedi in hiding could return if they rebuild the Order, especially Yaddle. She has yet to make a reappearance during the Skywalker Saga timeline. Yoda and Obi-Wan Kenobi survived Order 66 and remained hidden from the Empire for many years, eventually going out on their terms. If Yaddle did retire shortly after the Battle of Naboo, she had a thirteen-year head start on most survivors. That is plenty of time to go back to her homeworld, which like her species, is a mystery. Whether either remains a mystery is yet to be seen, but introducing Grogu in The Mandalorian makes things interesting.
Grogu is the youngest we have seen from the species and would have been born shortly before the time of The Phantom Menace. He has family somewhere and, being at the Jedi Temple would have come into contact with Yoda and probably Yaddle. If Yaddle were to return, it would make sense for her to retrieve Grogu from Luke before the Jedi Master trains his nephew Kylo. Now, whether fans are ready to see a female version of Yoda back on screen is another thing. First, her character would need a redesign to avoid the “Yoda with a wig” look and be more tailored to a younger female member of the species. A lot of thought went into the design of Grogu, and Lucasfilm would need to put in the work for Yaddle. Her speech pattern and voice would also be new. In legends, Yaddle’s speech pattern is similar to Yoda’s; however, in Out of the Shadows, it is a regular speech pattern similar to others that speak basic.
During the Disney Investor Day last year, Kathleen Kennedy mentioned that The Mandalorian, Ahsoka, and Rangers of the New Republic would “culminate in a climactic story event.” Rangers of the New Republic has since been put on hold and might not go into production, but the “story event” could still proceed, especially if the story event revolves around Grogu. If so, Ahsoka could run into Yaddle on her search to find Ezra Bridger. Yaddle could have also heard Grogu’s call and decide to come looking for him in a future season of The Mandalorian.
If they are not ready to bring Yaddle into The Mandalorian time, they can do what they have been for Jedi who live long lives: increase their presence in The High Republic. They have already established that Oppo Rancisis, Tera Sinube, and Yarael Poof are around during this time in prior novels, and now with Out of the Shadows, so is Yaddle. They can expand on that and give her more focus in future content like IDW’s The High Republic Adventures since she also works with Younglings. If they keep Yaddle in distant Star Wars past (I know everything in Star Wars is a long time ago), that would be a shame. The opportunity is too great to bring her into one of the live-action Disney Plus shows. Perhaps she can even show up in the only announced live-action series that will take place during the High Republic era, The Acolyte.
Yes, Yaddle started as a sketch of a younger Yoda, but she has evolved beyond her silent stares and bad wig to one of Star Wars’ biggest mysteries. And while some secrets like her species and homeworld should stay put, plenty of fans would welcome Yaddle back into Star Wars relevancy with open arms.