History of the kagami clan according to Takumi Karasuma
The Kagami Clan (嘉神家, Kagami-ke) is a family of legendary shikigami users, which most are feared because they never showed themselves on the front lines as their shikigami techniques are secret. People were once afraid of them because they could overthrow a country, so they were called the "Kagami Demons" because they lived in the boundaries between humans and spirits. Kaian Sumeragi of the Sumeragi Clan was the one who bring the clan out of isolation.