"Melee weapons are used in close combat only. They generally don't do a lot of damage, and don't require too much strength to use, however player's with higher strength will have a higher rate of fire and do more damage. The melee weapons are ritualistic knives, tailored to each "Chosen" member separately. In addition to being quiet weapons they become more powerful the more they are used."--Blood II: The Chosen Manual
The knife is the melee weapon of Blood II: The Chosen, replacing the Pitchfork. Caleb starts with it, along with the Pistol. It is meant to be used in close combat and has an even shorter range than the pitchfork in Blood.
Players with higher strength will be able to activate the knife with more speed and cause more damage. The Blood II instruction manual says that each knife has been tailored to fit each of the Chosen and that it becomes more powerful with each use, but the game dynamics do nit support this without the use of a third-party modification such as FX Enhancer or Extra Crispy.
Each of the Chosen do have a different model of knife, however. Caleb has a Bowie Knife, while Ishmael's has a more twisted version with a barb on the back, looking more like a sacrificial knife. Ophelia brandishes a long and thin blade, perfect for quick silent attacks, whereas Gabriella wields a more military-looking massive blade.
Deleted parts of the storyline seem to indicate the knife had more purpose than as simply a melee weapon:
None of us knew what the rifts were or where they came from. But we all saw them as the same thing – power. A way for us to destroy each other more efficiently. All we needed was the proper artifact to control it – the channeling knife. An ancient artifact of the Cabal, it lay broken in two pieces somewhere in Old Town, and the Cabal was determined to find it first.--Gideon, deleted audio clip from Blood II
AMMO TYPE: None
REGULAR FIRE: A single slash from left to right
ALTERNATE FIRE: Player reorients the blade to point down and slashes, increasing strength, but decreasing speed