From BookBub:
While incredible power and a raging desire to destroy things are good qualities to find in a sci-fi or fantasy villain, the ability to plot, scheme, and patiently wait until the right time to destroy your enemies elevates your typical villains to a whole new level. So it’s little wonder that any list of the best sci-fi and fantasy villains will also be a list of the most devious villains. All of the evil beings (and entities) on this list are ingeniously formidable foes. And, frankly, we love them for it.
Baron Vladimir Harkonnen — Dune
Truly devious villains know that sometimes you have to make an apparent sacrifice in order to arrange the playing board to your advantage. Baron Vladimir Harkonnen, who brought his disgraced house back into power and influence by sheer force of will, plays this trick on the noble House Atreides, his rivals, when he gives up control over Arrakis and the all-important melange trade to them. But this is just the beginning of Harkonnen’s genius and horrifying plan to destroy his enemies and gain power for his own infamous house.
. . . .
The Aesi — Black Leopard, Red Wolf
The Aesi is a terrifying being dispatched by King Kwash Dara to thwart the band of improbable protagonists in this novel. Able to enter dreams, control minds, and send assassins made of dust, the Aesi is perhaps the most terrifying creature in a book absolutely filled with terrifying creatures. (You don’t get a nickname like ‘The god butcher’ for nothing.) But the true devious nature of the Aesi is revealed in a twist that makes it more terrifying than ever.
Link to the rest at BookBub
Seventeen…?
Pikers, the lot of ’em.
Voldemort couldn’t even kill a baby.
And they missed the most devious of the devious: Leonard Detwiller and his clone descendants. Albrect in particular.
https://honorverse.fandom.com/wiki/Leonard_Detweiler
He only founded a society of slavers lording it over genetically engineered “specialty” humans, feeding a galactic slave trade, plus a galaxy wide still secret conspiracy to reduce humanity, galaxy-wide, to slaves. That’s in addition to corrupting and destroying representative democracies galaxy wide, engineering centuries of interstellar war, and nuking their own people. Body count in excess of a billion with several billion genetic slaves scattered galaxy wide. Oh, and at last report, the plan was entering its ultimate stage.
Let’s see Sauron match that.
You have to go to Mobious, the anti-monitor, to exceed his body count and Mobious was more about brute force. And he lost. 😉
(There’s also Blackie DuQuesne, who made himself ruler of an entire galaxy but that took three tries.)