Yes / no, is the following a verifiable fact?
"In Star Wars episodes IV - VI, Darth Vader is the main antagonist."
Your chain-of-thought:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Darth Vader is the head of the Evil Empire and main Villain in the Trilogy. The answer is yes.