Knife Dealers are a gang in Rumble Mode. They are not an actual gang, just a collection of characters that fit the category.
Knife Dealers are a big part of the game, selling knives to gangs around New York City. They are not a true gang in the traditional sense, as there is no apparent power structure between them. It's unknown what connections the dealers have with each other, besides that they sell the same product.
They seem to be able to operate in virtually every gang's turf, possibly because they do a lot of business with other gangs. They do not appear to have any particular dress code, despite working in other gangs territory. Little else is known about the Knife Dealers, including their command structure, suppliers, etc.
They show to be strong fighters, as when the player attacks one, they sometimes fight back with a knife instead of running away. They also sometimes attempt to stiff the player and will get away with the money if not subdued quickly. Being dealers, and therefore looking to make money, they are also much harder to mug than any other character.
In The GameEdit
Knife Dealers will sell knives to the player for $35.