The knife has has been used to kill demons, humans, and hellhounds.
The white-eyed demon [[Alastair]] was never killed by the knife's demon killing power since both times he was stabbed were on the left shoulder.<ref name="four09" /><ref name="four16" /> However, [[Sam]] noted at one point that Lilith herself was scared of the knife,<ref>[[4.02 Are You There God? It's Me, Dean Winchester]]</ref> and she continually took precautions to avoid being stabbed with it whenever confronted with it.<ref>[[3.16 No Rest for the Wicked]]</ref><ref>[[4.18 The Monster at the End of This Book]]</ref>
[[Crowley]], too, has always avoided being stabbed with the knife.<ref>[[5.20 The Devil You Know]]</ref><ref>[[6.10 Caged Heat]]</ref> While Crowley stated
in [[10.22 The Prisoner]] that the knife couldn't kill him, this may have been a bluff as he was later shown to be nervous in its presence when Dean pulled it on him after disabling him with an [[angel blade]].<ref>[[11.02 Form and Void]]</ref>
When [[Abaddon]] was stabbed by the blade, she survives despite experiencing intense pain, revealing that the [[Knights of Hell]] are partially immune to its demon killing abilities.<ref>[[8.12 As Time Goes By]]</ref> Unlike Abaddon, [[Cain]] stabs himself with the blade after Dean threatens him and suffers no pain or even any sign of exsanguination.<ref>[[9.11 First Born]]</ref>
After surviving a killing blow from the knife by Sam, it was revealed that [[Ramiel]] and all [[Princes of Hell]] are immune to the knife's power.<ref>[[12.12 Stuck in the Middle (With You)]]</ref>