Demons/Yokai occur in two ways.
Fifth Dimensional Beings Falling Down to The Fourth Dimension (The Adversarial Path) , or impure/evil/negative thoughts/energy rising from the 2nd/3rd dimensions into the 3rd/4th dimension (The Parasitic Path).
Fifth Dimensional Beings Falling Down to The Fourth Dimension (The Adversarial Path) , or impure/evil/negative thoughts/energy rising from the 2nd/3rd dimensions into the 3rd/4th dimension (The Parasitic Path).