A blue green jewel, Beta Delphini II, home of the turtle like Chelonians. The world is old, and bears many scars, the craters from orbital bombardment and high power explosions, rings of dust and debris that were once starships, habitats, and fighter craft. But the world below remains tranquil, its wounds covered with blue seas and green forests.
Nearly every primitive culture has had rituals and celebrations to guarantee the proper passage of the seasons and to ensure the fertility of crops and animals. Oversight of these ceremonies was generally the provenance of local kings or priests.
Suppose that the adventurers dispatch one of these fellows. The local peasants may become hysterical, fearing famine and death will stalk the land. Alternatively, they may want one of the new heroes to become king. For a while, this can be a good thing, but the first time that the crops fail, the superstitious locals will want to sacrifice their new leader.