So far, nothing is known of Psychaeus' origins before Facadma's possession of her (that's right, Psychaeus is a woman). The character traits she displays are not her's, but rather Facadma's. That voice that most hear from her: Facadma's. It's far more than a simple demonic possession, as she is consciously aware of her own actions, yet she can do nothing about them. She's forced to kill people she doesn't want to kill, and she's forced to say things she doesn't want to say. And those horns growing out of head? She did not always have those (so she's not a Zabrak). Those horns are growing right out of her brain and prevent her from telepathically communicating with others or others from reading her mind unless they are broken. What sucks even more for her is that she's mostly immortal (more specifically, she can live forever), and when she's not being used for genocide, Facadma's torturing her physically and psychically. The only thing that could possibly end her torment is for someone else to kill her. Getting out of her nightmare fuel-ish perspective, she can use the force to kill a planet's worth of people instantly in a manner similar to Darth Nihilus, but unlike him, she can selectively kill her targets. However, this power is also a result of Facadma's possession. She is the only known wielder of the lightscythe. By the way, that floating head sketch, that does not give any indication of what she actually looks like; it's just a concept for how the Facadma mask goes around her face. She is human or near-human (the mask structure simply reflects Facadma's face) and is wearing a black balaclava. Somehow, she is able to see what the mask can see.