In the Star Wars: Rebels episode "Trials of the Darksaber", unofficial Jedi Knight Kanan Jannus drops a history lesson to Sabine, a Mandalorian, stating that the Jedi won the war with Mandalore. This one-liner from Kanan connects the current Star Wars canon to the expanded universe, which was considered non-canon when Disney took over the reigns of the franchise, and LucasFilm as a whole.

Interestingly, the video game Knights of the Old Republic, part of the "Legends", tells the tale of the Mandalorian War, a battle wherein the Jedi defeated the Mandalorians thousands of years before the events of the original trilogy. Led by the Jedi Knight Revan, the Jedi Order joined the clash between Mandalore and the Old Galactic Republic. Revan bested the Mandalorian leader, Mandalore the Ultimate, which ended the war in favor or the Jedi and the Republic. Revan would later on join the dark side and become a Sith, then go back to the Jedi Order. According to SlashFilm, the story of the Mandalorian War was also depicted as a mural in the other animated series, the Clone Wars.

Now this has not been the first time something from the "Legends" would be pulled into the main universe, Comicbook reports. Taking a hint from Ahsoka Tano's statement in season 2 of Rebels, "There's always truth in Legends", Grand Admiral Thrawn, who was first introduced in the novel Heir to the Empire, was added to the cast on the third season as a recurring villain. It seems that slowly but surely, the extended universe is beginning to become a pool of backstories for the main universe.  

Now that the Mandalorian War has been confirmed as part of the universe canon, many are hoping that its main man, Revan, would be seen in the series somehow. Eager fans, however, would have to wait a few weeks, as the show is on break until February 18.