Regra De Dois by Drew Karpyshyn

After the fall of the Brotherhood of Darkness, a Sith Master and his young apprentice retreat into the shadows to rebuild their order under a ruthless doctrine allowing only two at a time. As he hunts forbidden lore and wrestles with parasitic armor that both empowers and torments him, she perfects deception and dark sorcery, infiltrating the Republic and manipulating allies and enemies alike. Their activities draw the suspicion of determined Jedi who launch a strike, culminating in a brutal showdown on Ambria. In the aftermath, a calculated ruse convinces the Jedi the threat has ended, allowing the pair to vanish and ensure their secret legacy endures.

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