The Dark Lord will require a new host soon. 

This is how you know money can buy anything. Do you know how unlikely it is to get one heart, yet alone a second one?

“Darth Plagueis was a Dark Lord of the Sith so powerful and so wise, he could use the Force to influence the midi-chlorians to create life. He had such a knowledge of the dark side, he could even keep the ones he cared about from dying.”