A tribal society which lives on the harsh Northern Plains consider it dishonourable to slay an enemy without looking it full in the face. Any missile weapon is treated with derision and contempt, while rangers and other archers are denied entrance to the tribal villages.
The population of a forested kingdom never reveal their names to any but their immediate family, and consider it a grave mistake when others do so.
The secret for immortality has been discovered by an eccentric wizard/mad scientist. Its found you need to reapply once a month. As people stop dying, and the birth rate increases exponentially, people are forced into homelessness, because of the need for food reamins the same, and food is not being produced fast enough to feed the undying population. The PCs have to find the creator and kill him, and destroy production, to save the world from undying, unending torture from hungryness.