Continuity mistake: Right at the start, when the woman says, "Why can't you be more like your brother?" the cereal the kid has changes position/amount between shots. (00:02:10)
Continuity mistake: After having shot Bo with a stolen crossbow, Carly and Nick search the Sinclair house for help. When Carly comes across a drawer filled with newspaper clippings and childhood photographs of the Sinclair brothers, Bo and Vincent are seen on these photos as having very fair, almost light brown hair, and yet in the film, the adult brothers both have very dark black hair. It is possible that they could have dyed it in the past, but considering one is a deranged psychopathic killer and the other his simple-minded disfigured sidekick, this seems very unlikely (admittedly, hair color can grow darker over the years, but not the the extent of changing color completely, and the photos of Bo and Vincent show them around 5 or 6 years old, not toddlers). (01:23:15)
Other mistake: Covering the victims' bodies with layers of wax would make the figures look unnatural large. And the machine that secured the victims in seated position as it sprays then with layers of hot wax would mean the figures would have to stay in seated positions when completed.
Factual error: Wax doesn't burn, even when exposed to flame. Wax also will not conduct heat. The ending shows the House of Wax melting and burning to the ground, as if the heat is spread throughout the house. In actuality, only the small hole near the fire will melt; the rest of the house would be unharmed.
Continuity mistake: When Wade and Carly first enter the church and think they have 'interrupted' the funeral, we see a close up of the priest's face. He looks like a real person just standing very still. Later in the film when there are more prolonged shots of the priest (when Carly hides under his clothes from Bo), you can see he is now a lot more 'waxy' and fake.
Continuity mistake: At the beginning of the scene when Paige and Blake are alone in the tent, there is a shot of Blake's cell phone sat atop a CD case, with the top line of the display showing the date and time and "NewVoiceMessage" below it. When the music stops and Blake runs out of the tent, the phone is seen in a different orientation on the CD case but still has the date/time as the top line. After Blake restarts the music, he then picks the phone up, which is still in its new position but no longer has the date/time displayed on the top line. (01:08:10 - 01:09:45)
Answer: All we know is that he is the brother of Bo and Vincent. He's a mystery. A hint to a sequel maybe?
Mortug