Set aside the morals
Don’t judge what he was doing, judge how he was doing it. By that criteria the name that pops up in my mind is Adolf Hitler. Without questioning his motives if we look at him from a leadership point of view, he was a very effective leader who convinced a huge nation that what they were doing was the right thing even though now what they did is condemned. His leadership qualities were:
The man had the ambitions of taking over the world which made his thinking process and his motivation to be of monumental proportions. He was driven by his goal, and his charisma and leadership style made him highly desirable to be followed by his people. All it takes is self-belief and a little sense of organisation and people skills. Some say leaders are born, others argue that leaders are sculpted by their circumstances. The debate of nature over nurture will always remain that, a debate. But leaders like Hitler are not born every day.