The Chaos Scar is a long, wide valley carved long ago by the fall of a massive meteor. As the giant rock passed overhead, milk curdled, livestock fell over dead, and ill fortune befell all. The meteor crashed into the earth with deafening force, and red radiance lit the sky for a week. Then it vanished.
The meteor had carved its massive gash in a dark and wild place between points of civilization. Where once had stood a wild forest and swamp between a line of small hills was this new valley—the Chaos Scar.
Over a mile long and several hundred feet deep, the Chaos Scar is a testament to the vast power of the meteor’s impact. As it carved its path through the earth, shards and fragments of the meteor tore away until only its heart remained, embedded in an escarpment at the far end of its new home. There, it sent out its call. Over the centuries, creatures of evil spirit have been drawn to this beacon. The meteor's dark sentience spurred competition among them so that they fought with one another. The weak were killed or pushed to the edges of the meteor’s influence, while the strong and cruel rose to the top of the pecking order.
Following years of conflict, a group has emerged to rule the valley. It calls itself the Brotherhood of the Scar. Some nearby cities and nation states believe them to be worshipers of Bane. Others think them servitors of Zehir, or possibly a demon prince. The order seems to have reached some sort of understanding with the meteor, because while the conflicts between the monsters of the Chaos Scar continue, the Brotherhood is left to its own devices. The Brotherhood built a keep around the meteor, and the other denizens of the Scar have carved out their own dominions within the valley’s many caves. The weakest settle near the mouth of the valley and the plain beyond, while the strongest lair closer to the valley’s terminus and in the fortress that now encloses the valley’s upper wall.
Some cities have tried to hem in the threat of the Chaos Scar, with little to no success. A long-forgotten ruler who fancied himself a king erected a wall across the valley’s mouth long ago. It still stands, partly in ruins, its gates open and unguarded. Towers that once ringed the valley have fallen to ruin as well. Some are inhabited by monsters; others are simply empty.
The Chaos Scar itself is death to most who wander in. It is filled with evil and riddled with caves both natural and tunneled by generations of monstrous denizens. The deeper one travels into the valley, the deadlier the foes lurking in its caves and hollows. Strange features have been raised, or have simply appeared, within the Scar—circles of standing stones, bizarre towers, grotesque cottages, and other more otherworldly features. Capping off the valley is the fortress of Hallowgaunt, home to the mysterious Brotherhood of the Scar, crowned by a perpetual storm of black clouds and crackling lightning.
Many adventurers have entered the Chaos Scar. Few have returned. Those that do weave dark stories of monsters working in concert as never before. Others tell of monstrous creatures working against one another. Welcome to the Chaos Scar.
...
You, however, do not wander your way to this part of the world without good reason.
Your party all hunt a gang known as the Brothers Gray, a small group known for a long streak of murders in thirteen different cities across four countries. The group has committed their own, personal crime against each of you, which has lead the members of your adventuring company to form, with the goal of finding and capturing, or killing, the Brothers Gray. After months of searching, you have finally discovered that the group have fled to a lawless region known as the Chaos Scar. Your justice, or vengeance, is approaching fast.
(Each of your reasons for hunting the group can be made public to your party, or kept entirely private, so long as you keep in mind what it is.)
You find yourselves at the gates of an ancient keep known as Restwall Keep, one of the last bastions of civilizations on the fringes of the Chaos Scar's malicious reach. A tired guard sits in a small watchman's post before a raised drawbridge. She watches you approach, and instinctively gives her 'scpheel.
"Hello, and welcome to Restwall Keep. Due to the importance of security, I will need each of your names, professions, and reasons for your business in our city before you can enter. Thank you for your understanding."
The guard reaches down behind her desk, and pulls forth a telegraph. She sets it gently in front of her, and returns her attention to your party.
"Now than, who first?"