Trevor Slattery wasn't a true villain in Iron Man, but his actions allowed the real villain to carry out some serious terrorist activity unopposed and, as a result, he was indirectly responsible for thousands of deaths. He did so by stupidly allowing himself to be manipulated into posing as the villainous "Mandarin" while Aldrich Killian carried out a string of bombings that killed a lot of innocent people. The big reveal showed Slattery to be nothing more than a bumbling, alcoholic British actor who, desperate to resurrect his failing career, took on the ultimate role that would fool the world - all while being given all the drugs, booze, women and luxuries he could possibly hope for. Inevitably, he was found out and sent to prison - which is exactly what his stupidity and irresponsibility deserved.
