Morag McLaughlin, shortly known as Morag is the main antagonist in The Loud House Movie. She is introduced as the caretaker of Castle Loud and is a complete opposite to her co-worker, Angus the groundskeeper. She enjoys having nothing more than deafening silence and, needless to say, is not at all pleased when the modern-day Loud family arrives in Scotland to learn about their ancestry. In addition to her disdain towards the noisy family, she also does not care about coming to the aid of the villagers in Loch Loud, whom she considers to mere "peasants".
Over the course of the movie, it is revealed that Morag's ancestor, Aggie, who was the castle's caretaker during the lifetime of the 1600s Loud family, had successfully forced them into exile by using a magical gemstone, called the Dragon Stone, to turn their pet dragon, Lolo, against them. Finding where Aggie hid her journal with the Dragon Stone included, Morag seeks to get rid of the Louds the same way her ancestor did and then steal Lincoln Loud's royal title of duke. Morag tricks Lincoln into riding his family's new pet dragon, Lela, over Loch Loud. During Lincoln's flight, Morag uses the Dragon Stone to take control of Lela and has the dragon wreck the village, getting everyone in town mad at Lincoln and making him so ashamed that he abdicates his royal title.
With the Louds out of her hair, Morag crowns herself as the new duchess of Loch Loud, telling the citizens that the Louds asked her to take the throne. However, Angus objects and reveals to everyone that Morag is lying. When the citizens revolt against Morag, she unleashes Lela, still under her control, against them. However, Morag's reign of terror proves to be short-lived, as the Loud kids soon learn about her treachery and return to Loch Loud to defeat her. In the battle that follows, Morag outright attempts to murder the Louds and Angus by ordering Lela to incinerate them, solidifying her place as the evilest character in the series. In the end, the Dragon Stone is destroyed, and the now-freed Lela drops Morag on an island inhabited by a family of barking seals who resemble the Louds.
During the end credits, it is shown that Angus, having now been crowned as duke of Loch Loud, eventually takes Morag off of the island and back to Castle Loud, where she is now forced to serve the ghosts of the 1600s Loud family.