Nightmarens have 2 phases Pre-Conversion -> Conversion.

In Pre-Conversion phase, ,the first form of Nightmarens, they have a black shadowy mass, their eyes will always remain the same, bright and yellow. In this form, they can walk through walls, travel through darkness and change their forms at will. Their one flaw in this stage is inability to communicate with each other and people. Because of this most people do not know how to interact with Nightmarens given their mysterious nature.