Cool post! Welcome aboard! :)

Say though, do you like riddles? Because I've got a toughie! Let's say there was a group of people traveling around the region today, led by a charismatic speaker who claims the world is ending soon, but that he alone can save you if you sell your belongings, devote your life to him and cut off family members who try to stop you? He would also like you to leave your home and job if necessary to follow him.

What type of group is that? Do we have a modern term for it?