Cult Leader

The cult leader is a sneaky individual. Sometimes, cults are based off truth and legal but most of the time they're invented by one person (most of the time the cult leader), this person seeking possible economic gaine. 

What makes a good cult leader

 
A good cult leader's biggest strength is speech. He must know how to convince and persuade people to join his cause. He must know how to make grand speeches, using the right body language and words to get the listeners to really get invested in what he's saying. 
A good cult leader must know how to sell his cause. Some cults have an entry price but if the cult leader is good at communicating how great what he's doing is, then the potential followers won't care. Cults are a type of religion, the cult leader must know how to use this to his advantage. He knows that there is nothing scarier to his followers than death and he must use this to rally a maximum amount of people. 

A Man in Disguise

A cult leader may sometimes not be what he seems. Behind his flashy smile and kindness may hide an evil man hell bent on world domination or personal gaine. He may use his power over people to bend them to his will, brainwashing them. Some cult leaders have access to their members bank accounts and milks them to finance their dastardly deeds. 
When man has power, he always wants more of it. This is no different for the cult leader. He always wants to gather more people under his wing. Cults usually start in isolated environments (as seen in Resident Evil 4) and the cult leader quickly wants to expand it to the rest of the world. 
A cult leader will stick to his beliefs until the bitter end, sometimes taking his followers with him.