Even Christianity began as a cult. The first requirement when considering cults is the raison d'etre for the existence of the cult. Historically speaking, cults are usually distinguished by beliefs in opposition to orthodox religious practices e.g. the Flagellants of Renaissance Europe. In these situations cult exists to promote these unorthodox beliefs and provide refuge for true believers. In a gaming context cults may be formed for a number of reasons other than to simply worship demonic forces from beyond.
Spiritual beliefs are usually the major spur for a cult.
Many Christian cults were formed during the Middle Ages by false messiahs or heretics who challenged the rulings of the Catholic Church. Most, including the famous Knights Templar, were suppressed by the Inquisition as potentially damaging to the fabric of Christianity. Notable exceptions include the Protestants and the Lutherians, both of which have become religions in their own right. In modern times the controversial Church of Scientology has begun to take steps to be recognized officially as a religion. Mutual protection is another common motivation for the formation of cults, or more accurately secret societies.