*In earlier seasons, the knife is generally called Ruby's Knife by the characters. Its referred to as just the Demon-Killing Knife by [[Mary Winchester]] in [[14.01 Stranger in a Strange Land]]. Additionally, Dean calls it a Demon Blade in [[12.06 Celebrating the Life of Asa Fox]] and explains to a room full of hunters that it kills demons, "kills them dead."
*Though the knife played a role as the Winchesters main demon-killing weapon in the earlier seasons, it has lost its prevalence in the later seasons, particularly after the revelation that [[angel blade]]s can also kill demons. In the later seasons, the Winchesters use angel blades to kill demons more often the knife which then typically only appears once or twice a season.
*Hunters unconnected to the Winchesters don't appear to be aware of the knife's existence. In [[12.06 Celebrating the Life of Asa Fox]], [[Bucky Sims]] compares the temporary effects of an [[exorcism]] to the effects of an [[angel blade]]. In the same episode, when Dean shows the knife to the other hunters gathered, they are confused, causing Dean to have to explain what it is and its purpose despite the same hunters earlier talking about the Winchesters' legendary reputation.