The Primeval is a reflection of a prehistoric Earth. It is a world of animal fury: great dinosaurs, from massive Tyrant Lizards to flights of Pteranodons, compete to rule the ancient rainforests. It is also a world of spirits, beings of pure soul force pursuing their own agendas. Caught between the bestial rage of the dinosaurs and the mysteries of the spirits are the Kinfolk - a tribe of primitive humans searching for path in a ruthless world. The shamans of the Kinfolk strive to lead their people to survival, but even the greatest of them cannot comprehend the Crystal Core, a vast and strange formation radiating a terrible energy from the edge of the known world.
The Primeval is a savage world. Combat is brutal and dangerous. The Spirits are strange and powerful. Many animals and dinosaurs are as intelligent as humans or more so. Animals and dinosaurs can communicate with others of similar species. Spirits can communicate with all beings.
It is always night. The enormous Moon is always full and visible in the sky (characters who are werewolves in the waking world may have reactions to this they can decide for themselves).
A very skilled human warrior might defeat two or three average warriors.
A human warrior and most animals are equal in combat power if equally skilled.
An average success from a human or animal combatant will usually wound a similar NPC. A great success will usually kill a similar NPC.
A megabeast NPC is the equal of several warriors or smaller animals. A great success will wound a megabeast NPC, and several will be needed to kill one. Average successes usually have no effect.
Spirit NPCs vary widely in strength.
Shamanism can only be used to combat spirits or to roleplay thematic 'rituals', which players are encouraged to be liberal with. An average success will weaken or harm a spirit NPC. A great success will banish it temporarily. An average success in a ritual will accomplish the shaman's goal, but with a twist or hidden cost. A great success will do exactly what the shaman desires.