The word "Halloween" has its origins in the Catholic Church. It comes from a contracted corruption of All Hallows Eve. All Hallows Day, or All Saint's Day, November 1, is a Catholic day of observance in honor of saints. One story says that, on that day, the disembodied spirits of all those who had died throughout the preceding year would come back in search of living bodies to possess for the next year. It was believed to be their only hope for the afterlife. The Celts believed all laws of space and time were suspended during this time, allowing the spirit world to intermingle with the living.
The living did not want to be possessed. So on the night of October 31, villagers would extinguish the fires in their homes, to make them cold and undesirable. They would then dress up in all manner of ghoulish costumes and noisily paraded around the neighborhood, being as destructive as possible in order to frighten away spirits looking for bodies to possess.
The thrust of the practices also changed over time to become more ritualized. As belief in spirit possession waned, the practice of dressing up like hobgoblins, ghosts, and witches took on a more ceremonial role.
So, although some cults and devil worshippers may have adopted Halloween as their favorite "holiday," the day itself did not grow out of evil practices. It grew out of the rituals of Celts celebrating a new year, and out of Medieval prayer rituals of Europeans. And today, it is only as evil as one cares to make it.
