Many terms in Star Wars have always been a little nebulous, often used for how they sound rather than with precise definitions. And one such phrase, Jedi Master, has now been officially clarified to the extent that it seems Leia was the only Skywalker who could technically lay claim to being one.
The Star Wars Book explains what each of the six ranks within the Jedi Order – Initiate, Youngling, Padawan, Knight, Master and Grand Master – refer to. Master, rather than merely a generic title used to suggest advanced lightsaber skills and powerful Force abilities, is a station for which a Knight is only eligible after they’ve successfully completed the training of at least one Padawan. As such, the Skywalker family’s rocky relationships with their apprentices mean that Leia is the only member who actually qualifies.
Anakin could never have been considered a Master since his Padawan Ahsoka become disillusioned with the Order and left before her training was finished. And Luke fared even worse, with his first Padawan falling to the Dark Side and becoming the Sith apprentice Kylo Ren, while his other students were killed when Kylo summoned a lightning storm to destroy the makeshift Jedi temple. Luke also began teaching Leia, but she cut her own training short when she sensed that continuing down that path would result in the death of her unborn son.
The novelization of The Rise of Skywalker revealed that her tutoring was eventually completed by the Force ghosts of Obi-Wan Kenobi and Yoda, though, meaning that she could be considered a Knight. And while Luke began Rey’s training, they were only together for a few days before the death of the Jedi legend, with Leia continuing things during the unseen year following the events of The Last Jedi.
A Padawan typically becomes a Knight after passing Trials designed to test the core tenets of a Jedi, although they receive exemption should they overcome a particularly taxing challenge. Rey, after facing down the resurrected Emperor Palpatine and dying in the process, endured a greater test than any Jedi before her, which would automatically qualify her as a Knight. This means that Leia’s teachings were the only ones of a Skywalker that ultimately proved successful, making her the family’s one true Master.