The weapon you carry at the alternative of your pistol. When equipped, you can sprint faster. At a price, the damage goes down though.
At half of what basically the pistol does, the knife does about 20-25~ damage, and this can also be a less suspicious weapon to deceive with.
While the knife is great and all, it has different skins. Such as the Special Knife, Elf Knife (for the holidays), the Spoon, and a character's own unique one,
Take Lisa's Tonfa, Nina's Microphone, or Hans' Wrench as an example. This isn't a weapon you can trust, but at the same time, you can never trust the pistol.
-Knifing sometimes is easier to aim, but it needs you to be close to target, if you aren't careful, you might end up dead.
-If you see someone drinking blood, change the weapon to pistol if you can, since if the target runs, you can't knife it easily, and he might transform.
-You can use the Slasher perk from a perk tree to increase the damage of the knife.