Not for the sith mastery claim, its very natural after all, every sith wants to be a master. I mean was that the right time for killing Plagueis ? Sidious doesn't have the enough power to defeat Plagueis in direct duel, and against Mace Windu or Yoda the conclusion will always be uncertain at that power level of his. Mace Windu could end the sith line in coruscant duel if not for Anakin's betrayal, and Yoda duel was also difficult, however with the power of the Darth Plagueis I doubt Windu or Yoda could defeat them... Thoughts ?