Satine Kryze is the Duchess of Mandalore and leader of the New Mandalorians, introduced in the second season of Star Wars: The Clone Wars in 2010. She governs a world that has renounced its warrior tradition, disarmed, and declared neutrality in the Clone Wars — a position that makes her simultaneously the most principled and the most precarious head of state in the setting.
The policy, and its enemies
Her pacifism is not a personality trait; it is a programme. Mandalore's warrior clans were, in the New Mandalorian account, exiled to the moon Concordia after generations of war that nearly destroyed the planet. Pre Vizsla's Death Watch and her own sister Bo-Katan Kryze regard that settlement as a surrender, and spend three seasons proving that a disarmed state cannot defend a policy of disarmament.
Kenobi
Her relationship with Obi-Wan Kenobi — a year in hiding together during his apprenticeship, and a mutual attachment neither of them acted on — is the most sustained romantic thread the Jedi Order's rules ever get tested against on screen. It gives the Order's prohibition on attachment a face rather than a doctrine.
How it ends
Death Watch's campaign succeeds, her government falls, and Maul kills her in front of Kenobi specifically in order to hurt him. Mandalore never recovers: everything from the Imperial occupation to the Purge to the fight over the Darksaber follows from the collapse of her state. She is the rare Star Wars character whose defeat, rather than her victory, is the load-bearing event.