“Castle” opens the main gates to enter the Badlands, the booming metropolis where Halsey says “cognitive activity happens” in correlation to her state of mind.

Castle was first used in promotion for the 2016 film, The Huntsman: Winter’s War in November 2015. The song was featured in the film’s first official trailer. On April 8, 2016, a more cinematic version was released to coincide with the film. Halsey was also featured in a music video, stylized as the the evil Queen Ravenna.

https://www.youtube.com/watch?v=Vk0xkd8qs9I