Before you send your hate mail, let me explain: Petyr Baelish (Aidan Gillen), aka Littlefinger, was one of the smartest men in all of Westeros, and from the beginning he worked tirelessly to maintain power. His cunning behind-the-scenes work fueled tensions between the Starks and the Lannisters, placed him in control of the Vale, and earned him the ear of some of the most prominent leaders throughout the Seven Kingdoms.
Often called Machiavellian, Littlefinger was a slimy man, but it was his unwavering devotion to deception and prestige that made him so incredible — and dare I say vital? — to the show.
"He’s just one of those guys you know is going to give you something good. And with Aidan you don’t know what he’s going to give you," David Benioff told EW. "He’s able to change things in ways that are strange and beguiling, yet to the betterment of the character and the show. Littlefinger is a much different character than we initially imagined, and the bulk of the credit for that goes to Aidan."
Weiss agreed, saying that Gillen "almost turns Littlefinger into a mystical embodiment of will-to-power and thriving on chaos" and that "there’s something impenetrable to everything he does."
Without Littlefinger, neither Jon nor Lysa Arryn would have died, Ned Stark might still be alive, and Sansa might never have realized that deep down she's a total badass after being forced into terrible marriages and trusting Baelish for the better part of her life. Littlefinger played seemingly everyone, making backroom deals and befriending the most influential people so that he could one day turn use everything he knows about them as leverage to gain more control.
"It was one of the harder death calls we had to make," Benioff said, later adding: "Every scene he’s in manages to make you think about Littlefinger. And when he’s at the center of a scene — like his final scene in the finale — he’s completely mesmerizing."
GoT, though I'm sure still bloody and violent, would have been a lot more boring without Baelish's invigorating brand of betrayal, charm, cowardice, and deceit that gave its seven seasons plenty of suspense and drama. But as much as I loved his character, what I loved even more was that his death brought Sansa and Arya together and helped them realize that as long as they stick together their potential knows no bounds.
"We loved having Littlefinger along for the ride, but he f—ed with the wrong girls," Benioff said.