So since Mark Hamill is the king of voicing amazing evil characters, I have the headcanon that after the Battle of Endor part of Luke’s job for the alliance was making voice calls to various moffs and other ranking imperials pretending to be a recording of the Emperor saying THEY were in charge of the Empire if he died and letting the infighting speed up the imperial collapse.
Luke: Urgh, Leia, do I really have to do this?
Leia: I’m sorry Luke, you’re just too good at sounding evil.
Luke: Fiiiiine. *puts on incredibly evil voice* Hello, Grand Moff…
Han: *whispers* That is just freaky.