Yellin is a minor villain in the 1987 fantasy film The Princess Bride. He is the Chief Enforcer of Florin, which presumably denotes him as the leader of Florin's military forces.
He first appears when Prince Humperdinck informs him that assassins from Guilder had infiltrated the Thieves' Forrest and were planning to invade his wedding and kill Buttercup (this is a lie and is just an excuse for Humerdinck to empty the Thieves' Forest to prevent anyone from preventing the wedding) Yellin confesses that his spies had not heard about it but follows the Prince's command, mobilizing the Brute Squad to round up everyone in the Thieves' Forrest and have them thrown in prison. When one of the Brute Squad informs Yellin that a Spaniard (Inigo Montoya) was giving them trouble, Yellin orders him to "give him some trouble."
Later, Yellin is seen protecting the front gate of the castle with a group of sixty of the Prince's guards during the wedding when the "Dread Pirate Roberts" (actually a disguised Fezzik) confronts them, scaring every guard off except Yellin. When Wesley, Inigo and Fezzik confront Yellin and demand that he give them the key to the gate, Yellin initially refuses, but gives it to them when Inigo threatens to have Fezzik tear Yellin's arms off.