The Demanitus Device is the massive subterranean machine deep in the Corona mountains, built by an ancient engineer and inventor known as Lord Demanitus. The machine was built based on the knowledge of both magic and science and resided in the center of the Demanitus Chamber.
According to Xavier's description, eons ago, an evil warlock by the name of Zhan Tiri had a deep hatred for Corona. He cast a spell which caused a blizzard to sweep across the land and the storm destroyed everything in its path. Lord Demanitus used both magic and science to build the machine deep in the Corona mountains. Demanitus used this machine to change the direction of the wind, and it pushed the flurries out to the sea. Zhan Tiri had been defeated and the day was saved eventually, but some say the curse of the storm lives on and is waiting to strike again for Corona to be at its weakest.
In addition, Demanitus was in a constant battle with Zhan Tiri and his brethren. Over the years, Demanitus captured many of the evil spirits and imprisoned them in the chamber of the device.
In Queen for a Day, during the storm, Xavier told Rapunzel about the Legend of Zhan Tiri and the machine, but it was considered a fairy tale in Corona. As the storm got worse, Rapunzel decided to look for the device, accompanied by Cassandra and Xavier. Following secret markings on the walls in the sewerage, they found the passageway to the device. Regardless of some troubles, the device was successfully activated and stopped the storm over Corona. At the same time, the device also accidentally released an evil spirit that served Zhan Tiri.
In "Be Very Afraid", Rapunzel and Varian went to the underground cavern to deliver the solution on the red rocks to stop the fear power. When she, Varian and Pascal arrived at the Demanitus Device to encase the red rocks with the solution but it doesn't work on red rocks then Varian finds out that it only works on black rocks.
Sometime later, that led up to the events of "Cassandra's Revenge", Varian had made its underground chamber his second lab where he continues to work on the Demanitus Scroll. Varian had placed his findings and the scroll on the wall until Cassandra forced him to get rid of his findings, while his and Rapunzel's friends are trying to deal with a large part of the device that Cassandra cut down; that has destroyed what remains of the Demanitus Device.
Weeks later, the Enchanted Girl (a borrowed form of Zhan Tiri) expressed her gloating towards her ancient enemy and that he had lost. She then threw her boomerang right into to it, causing it to shrivel away into dust.
- Queen for a Day (first appearance and use)