I_AM_IRON_MAN But why must he obey his master? Has he been exposed to the dark side enough that he has an insatiable lust for its power, and so needs to obey and continue to learn from the Emperor? Does the Emperor now have some kind of power over either the suit or something else that keeps Anakin alive? Yes to all of the above. Right after Mace dies and Anakin swears loyalty to Sidious, the latter says they will discover the secret of "prolonging life" together. Remember, in the Opera scene Palps reveals that Plageuis had this power and made the mistake of teaching it to his apprentice. Sidious doesn't want to make that same mistake again. He'll use that power to keep Vader alive, but won't teach it to him because Sidious, like Palgeuis, has power and is afraid to lose it. That's why Vader dies once Palps is gone......he was keeping him alive through the darkside power he had learned from Plagueis.