Mother is a created being, like Zisser Vraal. Indeed, she was created by the very same man as Zisser using the remaining samples of Apex's genetic material after the creator's escape.
Mother can take many forms. The form she began with was towering, monstrous, and insectoid. However, upon learning to change her form, she has shown a preference for taking the shape of a little girl with a pair of antennae.
Mother was created to be incredibly intelligent. Her IQ likely dwarfs that of her creator's. She can learn any teachable skill or magic simply by watching it occur. Similar to Zisser, she has a tendency to consume anything and everything. However, her consumption serves a purpose. She can learn every detail about something by consuming it. For instance, were she to eat a single hair, she would learn what the owner of that hair looks like, how strong they are, and virtually anything else there is to know about the being the hair came from. She can even learn the thoughts and memories of a being, but she would have to consume its mind in order to do so.
She is also in total control of the all drones created by Doktor von Ziegler, except for Zisser, who was created before Mother and is unconnected to her hive mind.