The Dark Crystal: Age Of Resistance does a beautiful job building off the world that first appeared in the original film from 1982. One of the show's greatest strengths is in how it develops the Gelfling. In The Dark Crystal film, the only Gelfling audiences get to know are Jen and Kira. They've spent practically their whole lives in hiding from the Skeksis and Garthim, completely disconnected from their people's history and culture.
Age of Resistance is a different story entirely, as it takes place at a time when seven Gelfling clans existed. Their society was fully functioning and their numbers abundant. The audience gets to understand the Gelfling, to care about and explore their nuances even more so than with Jen and Kira in the original film. Many Gelfling are essential to the plot of the Netflix series, but, inevitably, some are more powerful than others.
Naia
Naia was clever enough to figure out how to free her brother Gurjin from the Castle of the Crystal, regardless of the many defensive precautions that the Skeksis had taken. Along with Gurjin and Kylan, she also sabotaged the Chamberlain's carriage, thereby freeing the captive Rian and stealing the Chamberlain's steeds.
She was instrumental in spreading the word of the Skeksis' evil, which helped convince all the Gelfling clans to put aside their differences and unite against the Skeksis.
Gurjin
Gurjin was the first person Rian told about what the Skeksis did to Mira. Helping Rian steal Mira's essence from the Skeksis and then sacrificing himself so Rian could escape the Castle of the Crystal with it proves how loyal and bold Gurjin could be. Through all their interrogations and despite knowing what the Skeksis were capable of, Gurjin bravely resisted and refused to help them locate Rian.
After escaping the Castle of the Crystal, Gurjin helped attack the Chamberlain's carriage and rescue Rian. Gurjin was also one of the most important and influential figures in uniting all the Gelfling clans and bringing them to Stone-in-the-Wood to openly defy the Skeksis.
Seladon
Seladon is one of the most complicated characters in Age of Resistance. Her strengths as a politician and diplomat made her a valuable asset in maintaining the rule of her mother All-Maudra Mayrin and the Skeksis. The ambition and desperation to please her mother and the Skeksis that drives Seladon sometimes clouded her judgment and did a disservice to her talents, though.
Still, Seladon was clever enough to preserve her position as the new All-Maudra and best Maudra Fara's challenge. Particularly as All-Maudra after her mother's death, Seladon made a number of mistakes, but she learned from Maudra Fara and others what it meant to be a good leader, eventually allowing her to become the All-Maudra that the Gelfling need as they resist the Skeksis.
Maudra Fara
Maudra Fara was the first Gelfling to convince her whole clan to revolt against the Skeksis. The Stonewood clan stood behind her in open rebellion, with the other clans yet to fully commit to the cause. She honored tradition but did not blindly follow those who she felt didn't deserve the mantle of leadership.
This is why she and her clan revolted once they learned of the Skeksis' treachery and why she refused to accept the naive Seladon as the new All-Maudra. Fara set a powerful example that the other Maudras learned to embrace, which helped light the fires of resistance and also helped Seladon grow into a true leader rather than just a pawn of the Skeksis.
Ordon
Rian's father Ordon is one of the most accomplished Gelfling soldiers in Thra's history. Years before the events in Age of Resistance, he wielded the Dual Glaive in an impressive and important victory over the Arathim. He became Captain of the Castle Guard, during which he trained his son Rian, Gurjin, and many other Gelfling into becoming the best soldiers they could be.
It took Ordon a while to see through the lies of the Skeksis, but, once he did, Ordon did everything in his power to protect his son. He was able to pull off a surprise attack against the vicious Hunter. Ordon broke the Hunter's mask and was strong enough to pull the Skeksis down into the Gobbles, though it was at the cost of his own life.
Tavra
A skilled warrior with patience and wisdom beyond her years, Princess Tavra was crucial to keeping the peace between the Gelfling clans. She was the closest confidant of her sisters Brea and Seladon respectively, making them stronger and ultimately bringing them together despite their differences.
Even when she was later possessed by one of the Threaders, Tavra was strong enough that she didn't lose herself entirely to the parasitic creature, with their minds even merging together. As both Tavra and as a host for the Arathim, she grievously wounded the General and the Collector, which allowed numerous Gelfling to escape the Castle of the Crystal. If not for the Chamberlain's intervention, Tavra could've killed the General, thus avenging both All-Maudra Mayrin and the Arathim.
All-Maudra Mayrin
All-Maudra Mayrin inspired respect and obedience from all the Gelfling clans. The Skeksis' longtime partnership with her allowed them to maintain a firm and seemingly benevolent hold over the Gelfling.
When the All-Maudra finally broke free of the Skeksis' sway over her, her defiance proved to be a critical turning point. Her death shattered the facade of the Skeksis as benevolent protectors of the Gelfling. Their evil was exposed, and the unjust demise of such a respected and beloved leader helped unite the Gelfling clans against the Skeksis.
Brea
Brea's ability to question the things everyone else just accepts makes her the smartest of all the Gelfling. Her critical thinking also made her one of the most powerful, as she was rightfully suspicious of the Skeksis while the other Gelfling worshiped them. Such curiosity led her to unlocking the secrets beneath the All-Maudra's throne, where she figured out how to activate Lore.
Lore became an invaluable ally who saved Brea and other Gelfling on multiple occasions and brought them safely to the Circle of the Suns where they learned the truth that would ultimately help them defeat the Skeksis. Brea recognized that truth better than anyone when she spotted the shard of Crystal that was within the Dual Glaive, realizing that it could heal and restore the Crystal of Truth.
Rian
When Rian witnessed the Skeksis draining Mira of her essence, he was the first Gelfling to see through the lies of the Skeksis and live to tell the tale. With the help of Gurjin, he managed to steal Mira's essence from the Skeksis and escape the Castle of the Crystal.
The fiery, eye-opening speech he delivered to all of Thra fanned the flames of rebellion more than anything else and finally united all the Gelfling clans against the Skeksis. With aid from his allies, Rian found the two pieces of the Dual Glaive, brought them together again and wielded the weapon against the Skeksis, even besting the General in combat. In many ways, the resistance began with Rian and he became the face of it.
Deet
When the Sanctuary Tree transferred its powers to Deet, she easily became the most powerful Gelfling. No moment demonstrated this more than when she was strong enough to consume the power of the Darkening that the Emperor unleashed. Not only was she able to stop this power from killing her or her friends, but she was also able to hurl it back at the Skeksis and obliterate the Collector. This formidable act forced the Skeksis to retreat in fear. Deet also used the Sanctuary Tree's powers to heal creatures such as Nurlocs, who had been corrupted by the power of the Darkening.
Even before gaining the powers of the Sanctuary Tree, Deet was one of the most resourceful Gelfling. She knew how to make the smoke bombs that were integral in the fight against the Skeksis at Stone-in-the-Wood. Her genuine empathy and hope helped fuel the resistance in all the right ways, as well.