Madman

A group of senior counselors and campers, consisted of T.P., Betsy, Ellie, Dave, Stacy, Bill, and the middle-aged head counselor Max, are gathered around a campfire and tell the legend of Madman Marz; a murderer who murdered his wife and children with an axe, and was hung on a noose for conviction before he mysteriously broke free and escaped into the woods. Told by Max, he explains that anyone that says his name will awaken him and have him get that person. Richie, a cocky teenager, awakens Marz by shouting his name and throws a rock into his old home. Annoyed, Max then ends the campfire session and sends everyone to their cabins while he goes into town to stock up on supplies. Richie stays behind when he sees Madman Marz hidding in a tree and sneakily follows him back to his house. While everyone is inside their cabins, Chef Dippy is then killed by Marz outside.
After the kids have gone to sleep, the rest of the counselors go to the rec room to relax; T.P. and Betsy kiss in a hot tub, unbeknownst that Marz is watching them from outside. Meanwhile, Dave finds out that Richie didn't follow them back, and informs the counselors about this. T.P. searches out into the woods for Richie, and is hung by Marz with a noose up on a tree; he is killed when Marz pulls down his legs and the noose snaps his neck. Marz later returns to the camp and grabs the axe out of the log.
While Richie tries looking for a way back to camp, Dave ventures out into the woods due to Betsy worrying about T.P.'s disapperance, and is decapitated by Marz. Stacy tells Betsy to watch the kids in the meantime, and gets Ellie and Bill back to the camp due to the disappearances. Stacey drives out into the woods and, panicking from discovering Dave's headless body, tries to escape in her car in which stalls. She opens the car's hood, and Marz stands on top of the car just before he jumps down onto the hood, decapitating Stacy. Later, Ellie finds Madman Marz and screams, prompting Marz to flee and bringing Stacy's body with him. Bill soon arrives and consoles her while they try to head back to the camp using Stacy's car. Madman appears, and drags Bill out of the car to snap his back. Ellie is then chased back to the camp by Marz, and murders her with his axe.
Unable to find a way back, Richie goes back to Marz' house and is horrified when he discovers the corpses of Marz' victims stashed in the basement. Meanwhile, Betsy arms herself with a double-barrel shotgun upon seeing Marz running through camp, and quietly makes her way to the kitchen cabin. Marz then slams an wounded Ellie into a window, and Betsy accidentally shoots her. The gunshots awaken the children, and she tells them to pack up and get on the bus they took to camp to escape. Marz briefly tries to get into the bus with her, but she wards him off; she tells the bus driver to drive them out of the camp, and she chases after Marz to his home. Inside, she is disarmed and attacked by Marz, who drags her down to the basement and impales her on a coat rack. She pulls out a hunting knife and stabs Marz in the shoulder, causing him to knock over a candle which sets the house on fire, including the bodies of his victims. Madman Marz escapes, however, and disappears off into the woods.
Max drives to the camp, and almost hits a shaken Richie out on the road. He gets out to console him, and Richie tells him that Madman Marz is real.

Question: What sets the house on fire ?
Answer: A candle knocked down by Marz sets the house on fire.