Grindelwald let out a bored sigh already. Why were these Potters so annoying. "I heard him call you James," he said simply. Also they didn't seem as nearly as confused as they should be if the situation did not apply to this particular James.
"I don't have all day. Step aside, and let the boy come with me. It will be less painless that way. I only need him as a bargaining chip. If his father complies, than he will be free to go," Grindelwald explained. Though he knew these types, explanations and logic didn't work well.