Fae and Demons both share similar traits and derive from a shared ancestor species. Fae traditional follow hierarchy very seriously.
a small snippet of information given from "The Lost Queen"
"Let me explain the powers. Each fairy, except for celestial fairies, are born with a power they naturally come by. Fairies can learn to use other powers; it just won't come by as easily as their natural-born powers. When a fairy has parents of two different powers they have the more dominant power, except for some fairies, and the resistive power. The dominant power would be considered the natural power, and the recessive power could come by easier to learn rather than others. When it comes to Lunas and Solis powers those would always be equally as strong as each other. The children of a celestial fairy won't have as much difficulty learning other powers."
