    Harry nodded. "Purebloods," he echoed. In particular, Dark purebloods, because if Ron was at a loss to explain the behaviour, it probably involved something he was unfamiliar with. Harry could imagine, given what he’d read about most families that identified as Dark, that there were things the children in such families were expected to do, to further increase their families’ power and influence. He felt a moment of frustration – there was too much he didn’t know, too much he had yet to discover about this new world he’d found himself in.