Which character is most associated with a red lightsaber and a black cape in the original trilogy?

The story behind the answer

The iconic black armor and cape paired with a crimson lightsaber define the menacing enforcer of the Empire throughout the original trilogy. In contrast, the Death Star is a space station, Dagobah is Yoda’s swampy refuge, and Darth Sidious (the Emperor) appears hooded in Return of the Jedi and is not shown using a lightsaber in the original trilogy.

Red blades are strongly associated with the Sith, explained in modern canon as the result of “bleeding” a kyber crystal—symbolizing a willful corruption of the Force. The character’s silhouette and presence were crafted by concept artist Ralph McQuarrie and sound designer Ben Burtt, with David Prowse in the suit and James Earl Jones providing the voice, creating one of cinema’s most enduring villains.