Here are some Supernatural Facts!!
1: Mary's death compels John to become a hunter to kill the demon responsible, training his sons along the way. The influence of John Winchester is seen in the series even after his death, as the boys constantly reference his journal for advice. They repeatedly run into other hunters or civilians that knew John very well.
2: Ruby's knife functions similarly to the Colt, as it is able to kill most demons. Ruby never explains its origin or age, but is quite skilled in its application and use.
3: The Colt, and thirteen original bullets, were made by Samuel Colt for a paranormal hunter in 1835. According to legend, anything shot with it will die, including creatures normally immune to any and all weapons. It also serves as the key to the Devil's Gate. Colt used six of the bullets before it ended up in the hands of John Winchester, who gave it to Azazel in the second season.
There will be more facts soon.
