Imperial-Style is the style of onmyodo used created by Yakou Tsuchimikado.
A revolutionary magic system created by Yakou after gathering, breaking down, rebuilding and refining old Onmyoudo at the behest of military. Being the culmination of all of Japan's magical techniques, and knowledge it is highest form of magic in the nation's history. Because it was created for military and political purposes (and not civilian use) it removed many of religious and abstract elements of old Onmyoudo and focused on practicability.
Imperial Arts made use of several protocols and a technique called "soul manipulation" making it's spells capable of many possibilities and feats such as ability reincarnate or even revive dead which is impossible under the current magic system. Because of this it's considered much stronger, complex and varied than Common-Style. Officially, while many of it's spells are banned like Taizan Fukun Ritual, some are still are allowed use such as Far Step.