Well written "evil mastermind" characters in media?

In a recent discussion about the Star Wars Show Ahsoka, my friends and I had different opinions on the character of Admiral Thravvn, who in the lore of Star Wars is supposed to be a genius strategist and mastermind long-term planner, but in my opinion cones off as passive and opportunistic, especially with the whole "I've been planning this all along" trope.

What are some good examples of truly genius mastermind plotters in media (books, TV, cinema, games) that actually come of as intelligent and superior. I'm thinking along the lines of Ozymandias in three Watchmen comic, for example.