Custom among pirates to yearly vote for their leader. If a majority believed the leader was doing poorly they could hold another vote. Democratic except in times of battle and danger at sea. Could bleed that over to some 'honorable' bandits.
A comet flies through the sky every so many years. During this time no fire is able to be lit anywhere the comet is visible.
Sword sharpness is equal to the status and skill of its wielder.
After killing certain animals, if you drink their blood while performing a sort of ritual you will have visions and/or gain specific powers for an amount of time.
Good luck to drink out of wolve's paw prints or some other animal. Gives special powers.
Swords form a bond to their wielder. A symbol on the grip that is absorbed through the user's hand and appears on the back of the hand. Maybe only visible to them or others that have the abilities. Could give unique powers depending on when it happened and what they did to get it. It takes a specially made sword that only few can receive and made by a certain race. Then they must do something really heroic to unleash the swords power. Once unleashed it is theirs till they die then the sword goes dormant again till another accomplishes another feat.
People that live in cities no longer have any contact with the gods. There was a pact between the gods, humans, and animals. We could talk to the gods and the trees were the witness' to the pact. When the trees started getting cut down to make cities the pact was broken by the destruction of the witness'. So now only those that live with nature can speak to the gods and/or animals. Some trees grow tall creating darkness that scares men and they are not able to go near them. If they could they could again speak to the gods.
The PCs find a strange helmet, when donned it will take control of that PC and speak and act trough him/her. It explains that it is benevolent and needs their help in a quest and that it will stop possessing the PC when the task is done. Great if a player is gone for a number of sessions.