Star Wars: The Rise of Skywalker introduced the concept of the Force Dyad – an idea Lucasfilm has been exploring in Star Wars tie-ins and handbooks ever since. Every Star Wars film adds something new to the lore, and Star Wars: The Rise of Skywalker was no different. One of its most intriguing ideas is that of the Force Dyad, the name given for the mysterious bond between Rey and Kylo Ren that proved to be a wellspring of power greater than life itself.
Lucasfilm has always tended to use tie-ins, handbooks and the like to explore the ideas introduced in its movies. The Rise of Skywalker had many plot holes, ideas, and concepts that were only half-developed and really needed to be fleshed out. Consequently, it's fallen to books and comics, Visual Dictionaries and other tie-ins to explain them. The concept of the Force Dyad, in particular, has been richly developed off-screen, with Lucasfilm gradually defining its nature and history, and even hinting at its true potential. It's now possible to draw the threads together to present an almost complete picture of the Force Dyad, the unique bond in the Force that drove so much of the sequel trilogy's conflict.