The 18K Triad is the rival Triad organization to the Sun On Yee, taking real-life influences from the 14K Triad in Hong Kong.
18K are the strongest of the two Triads, and are fighting for superiority in Hong Kong's criminal underworld. They operate in the most profitable businesses - drug dealing, extortion, and so on - in order to make money to buy guns and influence in Hong Kong to use against the Sun On Yee. Some of the focus (mostly side-content) in the game is to stop the 18K from turning major profits or to get an advantage over them.
There are only four characters directly associated with the 18K - Johnny the Ratface, Four Finger Wu and Doctor Tsang (involving in organ harvesting), and Naz Singh, the 18K H.K.P.D. informant. These four members and the activities of the 18K is the only information known in the game, and other information is either suppressed or sketchy.
