The Demanitus Device is a massive subterranean machine hidden deep within the Corona mountains, built by the famous inventor and engineer Lord Demanitus. The machine was built based on the knowledge of both magic and science and was designed to alter the wind's trajectory in order to prevent a dangerous blizzard.
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, he 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 and 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.