"What kind of religion thinks that you can FORCE conversion with the blade of a sword?" Honestly, just about every religion that has gained enough political power to execute people has been guilty of this at one time or another: Hinduism, Buddhism, Mayan religion, etc. Do you count communism as religion (cults of personality)? Forced conversions on pain of death tend to have more to do with using religion as a tool to assert political control over others than a felt need to share "love your neighbor" or any other doctrine.