Okay, so... spoilers. She isn't a Shade, she's a Witch Hunter, trained by the Shade Durza to seek out magic and destroy or capture it in the name of the King. So right now she's been given the mission to find where the Rider Sword came from, and as this is the closest settlement to where it was found, she turned up here first. After sensing magic in Mashal, she started questioning people, and when they couldn't answer her questions she got violent and went to the house with the strongest connection to the magic (the oldest building in the town located at it's direct center) and interrogated the people who lived there. Of course, the spell on Mashal is incredibly old and requires more spoilers to the plot I'm not going to give just yet, suffice it to say that no current residents know about the magic in the town. Faced with this complication, she left a message to the people of Mashal by killing the family, a father mother and their young daughter, and then lighting them on fire with magic and investigating the home on her own. Finding no source, she refocused on her mission and went to find the body the sword had been taken from.

By the time she emerged from the house again everyone had barricaded themselves in their own homes to avoid her gaze and hopefully be spared her wrath. The family was left charring in the middle of the street. A number of people other than the five PCs are out of the village about now, so people are hovering by their windows and peeking out every now and again so they can allow their family inside when they come back to town.

The people are scared and horrified, seeing a random woman claiming to be an agent of the King terrorizing their town on the search for some kind of magic none of them know about. They're suspicious of each other because the woman was so adamant magic was in the town they think their neighbours must be hiding something. Mostly though, they're scared for their families.