Could it be jurion or who ever was the guy that really liked the president of shinwa? Because he was the one who made that shady guy give the drug to duke so that he'd kill jiwoo and perhaps he's going to kidnap or hurt her little brother so that either he would threaten her by holding the medicine he needed after the drug or he'd threaten him by holding her brother captive. To be honest, I don't know if that's what it will turn out to but I'll still put it as a spoiler