Explain why your sect (whether Catholic, Protestant, or Eastern Orthodox) pursued, tortured,& killed people?

If a Catholic, justify the Inquisition and other persecutions of "heretics" throughout the centuries, concentrating on why the Pelagianists, the Priscillianists, and the Manichaeans were persecuted; if a Protestant, justify the witch trials and the way that Protestants constantly hunted down native Americans until there were so few that the government could simply take their land; if a member of an Eastern Orthodox church, justify the persecutions of the Old Believers after the reforms of the seventeenth century.