Twisted Firestarter is a secondary quest in White Orchard. There are only a handful of non-humans in the village, and one of them is Willis, a dwarven blacksmith whose work draws customers from far and wide. Shortly before Geralt arrives, his forge burns to the ground, and Willis is convinced it was no accident.
Geralt investigates the ruins of the forge with his witcher senses and follows the clues to the arsonist, a local named Napp. The motive is as ugly as it is common in the North: hatred of non-humans. Along the way, drowners near the river may also get in the way.
When Geralt finds the culprit, he can bring him to Willis or deal with him differently, and the ending depends on that choice. It is a small quest, but it shows early on how racism runs through the everyday life of the Continent.