"And yet he managed to be forgotten. Such a pity."

This emperor wasn't that insecure about his legacy even now since he knew that he was only getting started. Starkiller was just the beginning- he was young and had resources even Darth Sidious hadn't known about. Jedi and Sith Lords had become too dependent on the Force, forgetting that their power didn't make them able to rule a galaxy.

"I have no misconceptions about how fragile my own life is. You could kill me now and while I'm sure I could hurt you in the process, you would most likely win the fight with your use of the Force. But what I've built, my impact on the galaxy, isn't that fleeting."