Realmatic Theory was first used in Dragonsteel, Brandon’s second book set in the cosmere. The opening chapters include someone learning about the three Realms in a classroom. As Brandon wrote more cosmere books, he noticed patterns in the themes. He began to create a common energy source for the magic systems to use. Linking the books and creating the cosmere grew naturally from those themes and connections. Within the currently published cosmere, the term Realmatic Theory has only been used once, by the Ire. Khriss has used the phrase "Realmatic Transition" in the Words of Radiance Ars Arcanum to describe the Surge of Transportation. She also used the phrase "Realmic transition" once in the essay on the Taldain system to describe how sand mastery works. The difference, if any, between these two terms is as yet unknown.