Muska is a scheming government agent who has been appointed to lead a military search for the ancient flying island of Laputa. To this end, he and his men have taken the young girl Sheeta into their custody, who is actually a descendant of Laputian royalty and possesses an etherium crystal that can be used to find and revive the lost skyborne nation. What the military are unaware of is that Muska himself is also a descendant of the Laputian royal line. His real full name is Romuska Palo Ur Laputa. While the military's goal is to plunder Laputa's lost riches and technology, Muska intends to take control of Laputa himself and use its power to conquer the world.
After finding Laputa and capturing the Dola pirate crew, Muska forces Sheeta to lead him to the center of Laputa and he takes control of the island fortress, deploying scores of robots to destroy the military airship Goliath. Pazu tries to rescue Sheeta from Muska's clutches but the children are cornered and held at gunpoint. In order to keep Laputa out of evil hands, Sheeta and Pazu use the ancient Spell of Destruction within Sheeta's etherium pendant which causes Laputa to fall apart. A burst of light erupts from Sheeta's crystal and blinds Muska, who staggers around helplessly as Laputa crumbles around him. While Muska's death is not shown on-screen, he undoubtedly perished, either crushed by falling debris or plummeting to his doom when the structure he was in crumbled away.