Erik Prince, the former Navy Seal who founded Blackwater, hardly seems like the type who dwells on corporate niceties. He was, after all, America’s foremost mercenary executive. But there he was in Beijing, bearing an unlikely gift for a man who might open China to a freelancer known for his band of private contractors. It was a copy of his Blackwater memoir, Civilian Warriors. With that 2013 introduction to Chang Zhenming, chairman of China’s powerful Citic investment conglomerate, Prince gained entry to a lucrative new market – and, now, new controversy.