Such a bloodied claymore has history way back through lines of father and son. In fact only one place near the handle still holds a metal tone, because of a magical barrier, and it has ingraved in it words that forever speak out to the swords bearer. Those words, like a guilty memory, can never be forgot.
“Thou who shall kill a sons father, shall then be killed by a fathers son.”
The Great White Dragon is rarely seen. Nobody knows where he slumbers, but they do know his cave is on one of the highest peaks in the world. Only few stories have made it to be Known about across the lands. Few ever made it back to there home villages to tell the story.
A king so vile and treacherous was cursed many centuries ago to forever roam the earth. He is now a serf of earths will and shall be anywhere needed to stop the destruction of earths its bueatiful landscapes and creatures.
After the PCs defeat (or force the rapid retreat of) a villanous necromancer/demon summoner, they discover a book. This book outlines how to summon a demon whose power increases according to the size of the summoning circle used to summon it. And after the PCs examine a map of the country, they find that the layout of the cities and roads match up with the required summoning circle. In fact, the final road that would complete the circle is currently in construction.
With anyone who can find out about the circle and the ritual to summon the demon able to somehow make the final road/line, and destruction of the cities and roads currently in existence out of the question (unless this is an evil campaign- that removes the moral quandary), how are the PCs going to solve this problem?