*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]].
*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.
*Throughout season 13, the Winchesters did not use the knife to kill demons at all, instead relying entirely on angel blades despite the fact that demons were a major enemy in that particular season. Though the knife appeared in [[13.08 The Scorpion and the Frog]], the only demon killed with it was [[Grab]] by [[Luther Shrike]] while Luther was unharmed when Sam stabbed him with it. The knife was once again used by Sam in [[14.01 Stranger in a Strange Land]].