One of the Ruanaught, spirits bound to the physical world by Heiavian, the spirit of rebirth. They are corruptions of the originl spirits created to rule over humans and protect them from their sinful past.
They're dark versions more or less. Less etherial, more matter. They can't disappear like the spirits can, but because they're closer to actual matter, their powers have a stronger effect on the physical world.
That said, their power isn't as far reaching either. They need more servants to keep the elemental currents under control.