Star Wars: Bo-Katan's Backstory Explained

With plenty of experience resisting rulers of Mandalore, Bo-Katan and the Nite Owls survive through nearly two decades of Imperial control before being brought back into the fray when Clan Wren rebels against the Empire and Clan Saxon, as shown during Star Wars Rebels. The Mandalorian Sabine Wren (Tiya Sircar) offers Bo-Katan the reclaimed Darksaber, and with it rule of Mandalore, but Bo-Katan refuses it, saying her time as regent was a failure.

But after continuing to fight alongside Clan Wren, and helping to destroy the Imperial Arc Pulse Generator capable of easily killing Mandalorians in their beskar armor, Bo-Katan comes to accept her leadership role, and once again accepts the Darksaber and the responsibility of wielding it.

Then The Mandalorian comes along and reveals that she no longer holds the weapon. She asks the captain (Titus Welliver) of the ship they're hijacking where it is and whether "he" has it, and he tells her if she's asking then she already knows the answer. 

The episode doesn't go into how Moff Gideon came into possession of this fabled weapon, as seen in Chapter 8. It would make sense for him to have obtained it during the Great Purge, the Imperial action against Mandalorians throughout the galaxy that drove them into hiding, but Mando doesn't stick around to get the whole story. He's pursuing another lead, one on the Jedi Ahsoka Tan, and so fans will have to wait to see if The Mandalorian reveals exactly how Bo-Katan was forced to give up her role a second time, and how she plans to get her revenge on Gideon.