Please answer the following question: This article: Novelist Geoff and his wife Sally rent an isolated countryside bungalow to enable Geoff to finish his latest book without the distractions of life in London. On their arrival, they are horrified to find a dead man in the property; before they can report the discovery they are confronted by Duke, a gangland boss, and his henchmen who have, it transpires, been using the empty property as a hide-out for stolen valuables which they are planning to smuggle out of the country. A rival gangster, Juan, also has his eye on the goods and has discovered their whereabouts. The dead man is one of his minions. Geoff and Sally are held captive, and matters take a turn for the worse when Juan and his men also arrive on the scene, forcing a stand-off between the two factions during which Geoff and Sally are roughly-treated by both sides. Duke starts to fall for Sally, and his obvious interest in her antagonises his girlfriend Rina. Eventually there is a bloody shoot-out between the rival gangs, with Duke's men getting the better of the exchange. Duke boards a plane to make good his escape with the valuables, but the plane is shot down by the jealous and vengeful Rina. contains an answer for the question: Who is Juan's rival?, what is it ?
A:
Duke