Palpatine was the greatest Sith Lord in both Star Wars continuities, but the Legends timeline introduced the Dark Lady of the Sith, Lumiya, a villain who rivaled even Darth Sidious. Following their apparent destruction during the Ruusan Campaign, Darth Bane established the Rule of Two as a means of mitigating the inevitability of betrayal among Sith and to allow them to undermine their ancient enemies, the Jedi.
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