Number knives are a series of knives in the Mad Murderer 2. They are scattered in all tiers excluding bronze and unobtainium and are rarely earned through crafting and unboxing. All of them are similar in appearance to the Stock Knife, but their hilt is tinted to the colour of the tier they represent and have a hash tag on the handle and their respective number on both sides of the blade. When player has one of each number knife in their possession, they can be crafted into an unobtainium knife.
There are 10 number knives to collect:
For similar set of guns, see number guns.