Prince Humperdinck of Florin is the main antagonist of The Princess Bride.
Humperdinck is initially betrothed to the Princess of Guilder (Florin's sworn enemy), but upon discovering she is bald, Humperdinck calls off the engagement, and orders his men to search for a beautiful woman; Count Rugen eventually comes across Buttercup, and reports to Prince Humperdinck.
Three years after Buttercup's lover Westley is supposedly murdered by the Dread Pirate Roberts, Humperdinck hires a trio of criminals: Vizzini, Inigo Montoya, and Fezzik to kidnap Buttercup and kill her, framing Guilder for the crime so that he can start a war and conquer them. Westley, who had survived and became the Dread Pirate Roberts, follows them, defeating them systematically, and saves Buttercup.
After tracking them through the fire swamp, Humperdinck reclaims Buttercup and throws Westley into the Zoo of Death (the "Pit of Despair" in the movie'), his secret dungeon, to be tortured by Count Rugen, his second-in-command. When Buttercup threatens suicide if she is not reunited with Westley, Humperdinck pretends to respect her wishes and send for his rival's return, confident that the other man will be dead long before the wedding.
When Humperdinck accidentally reveals that he didn't send for Westley, Buttercup loses her temper and calls him a coward. Enraged, he descends into the Pit/Zoo, where Rugen has Westley attached to a machine that drains years of life away, and turns it to "maximum", leaving him "mostly dead".
He forces Buttercup to marry him later that night, planning to strangle her and blame it on Guilder. He is thwarted by Westley, who returned to life with help from Fezzik, Inigo and Miracle Max, the king's former "Miracle Man" Miracle Max who had been fired by Humperdinck. Westley challenges him to a duel, even though Westley can barely stand due to the aftereffects of being resurrected. Humperdinck is unaware of Westley's condition and agrees to duel him "to the death!" But Westley warns him that it will be "to the pain" instead, and explains what this means: he will not kill Humperdinck but leave him hideously deformed. Terrified, Humperdinck surrenders, and is left tied to a chair in the honeymoon suite of his own castle as Westley escapes with his bride. In the book, his men save Humperdinck, and he pursues the 4 heroes (Westley, Buttercup, Fezzik and Inigo), leaving the book on a cliff-hanger.
Prince Humperdinck is incredibly intelligent, cocky and has excellent tracking and hunting instincts. He can track the location of animals, and is able to trace events that have happened in a particular place. Buttercup herself says there is no greater hunter than him, proclaiming that he "Can track a falcon on a cloudy day."
Humperdinck is described as the finest hunter in the world; his tracking abilities are so great that he is able to tell which of two sets of tracks belonged to the loser of an hours old sword fight, and to determine that a wrestling match had occurred between a man and a giant. Behind his princely demeanor, however, he is vain and cowardly, "with a heart full of fear".
In the film, Humperdinck is portrayed by U.S. actor Chris Sarandon.