Zibong
The origin of the Zibong is nothing if not uncertain. It is rumored that they began as little more than a collection of spirits. Whose spirits, I cannot say. They possessed one profound advantage over most other noncorporeal enitities: unfathomable intelligence.
Centuries, if not millenia, ago, the Zibong had few, if any, special capabilities. These early Zibong are believed to have preyed upon a race of beings whose name has long since been forgotten. These beings were masters of magic and stealth. They would attack from a distance, then vanish into the darkness.
Were they not a peaceful race, they might have conquered much of the world. Instead, they concentrated on gathering knowledge and exploring unknowns. Despite a valiant fight against the relentless Zibong, the entire race was defeated.
For countless years since their victory, the Zibong have been silent. Most doubted their existance until recently. It is not known why the Zibong have become active again. Perhaps they have been ravaging other lands all this time and only known have reached the Nexus. Perhaps some great power has awakened them, either accidentally or with a malevolent purpose. Perhaps they had been feeding on the spirits of their previous conquest and only now hunger again.