Hi Bones,
What you describe definitely sounds like an extreme case and horrible. The N to whom I was married was stepfather to my kids... thankfully, only for a few years.
I can say that he did his best to control or manipulate them, but utterly failed. They saw clean through him from the get-go, but didn't tell me till after he was gone. One of his favorite tactics was to always do the opposite of whatever it was he knew they were expecting or needed at that moment .... typical. On the few occasions when he was called upon to drive them to school, he'd dawdle till the last minute before getting into the car. If one of them would dare to suggest that they were gonna be late, he'd drive as slowly as possible, just to antagonize them and exert his control. Many things along those lines... none too severe, but he definitely earned his nickname as "the shadow" around our home.
Hope