Triads had existed in China for centuries and were the most misunderstood, most complex, and most dangerous criminal organizations to infect the modern world. Chinese Triads made the Sicilian Mafia look amateurish.
Subject of a thousand Hong Kong movies and a recurrent trope in Western Yellow Peril stories, the Triads started life as anti-Manchu resistance during the Qing Dynasty. The official myth says that they were created after the burning of the southern Shaolin temple, by five survivors of the battle. Some claim that one of them was Jee Sin, who was the master of the 5 Elders of Southern Chinese kung fu. After the fall of the Qing dynasty in the last century, the Triads now found themselves without a purpose and there was a split between the Mainland and overseas branches. The Mainland group is what we now commonly refer to as the Triads, while the overseas group became known as the Hongmen. The mainland Triads now turned to crime as they were unable to reenter normal society. After the Communist takeover, many Triad members moved to Hong Kong and Taiwan to escape new measures against organized crime. Hong Kong's Triad problems peaked in the 1970s, helped by police corruption.
The Hongmen is divided into 180 branches, and is arguably a Freemason-like organization, with an emphasis on patriotism, given the circumstances of its origin. Distinguished politicians such as Sun Yat Sen and Chiang Kai Shek were senior members. It shares traditions with the Triads, since they were one and the same not that far back. They are illegal in Hong Kong due to their relationship with the Triads, but are legal in Taiwan as a secret society. Not surprising, since President Chiang Kai Shek was a member. They exist in China as a political party, and hold the single non-communist ministerial seat. It has branches in other overseas Chinese communities, where it is referred to as Chinese Freemasonry. Its membership is rapidly aging with the change in the times.
Another group are the Tongs, modeled on the Triads, which arose in the US in response to the need for support organizations for new immigrant Chinese, as well as taking charge of protecting their members from violence from other groups. Some Tongs are fully legitimate organizations. Others, not so much. Many Triad members would join Tongs on reaching America, causing some Tongs to be strongly influenced by the Triads.
Chinese secret societies are guaranteed to exist anywhere in the world with a significant Chinese immigrant population, from Australia to L.A.
The secret societies used to be governed by strict codes of conduct and an inflexible hierarchical system, but that system has broken down in recent years, leading to behavior that many older members would consider unethical. The traditional secret societies have 36 Oaths which basically say, "don't screw over your sworn brothers, or you will get chopped up with lots of blades." (This phrase is repeated many, many times during the oaths, just to remind you). Doesn't mention anything about the morality of killing innocents. The oaths are sealed with the drinking of blood mixed with wine, and the oath-takers enter into a sworn brotherhood with the rest of the members of their organization. No problems with having more sworn brothers from elsewhere, though.
As mentioned earlier, the traditional punishment is death by a hundred cuts, or getting ambushed and hacked up which is easier and quicker. Hong Kong triads especially love their cleavers, given the difficulty of obtaining guns in Hong Kong. A machete is fine too. Overseas groups may use guns, automatic weapons and explosives, if they don't find them dishonorable.
Some martial arts, especially some of the Southern Shaolin styles tend to have a reputation as being used by the Triads, especially due to their common origin myth in the Southern Shaolin temple.
The patron god of the Triads is none other than Guan Yu (of both literary and video game note). He is also the patron god of the police... and a patron god for business. Basically, Guan Yu is the god for any high risk endeavour where you want trustworthy 'brothers' watching your back.
Compare and contrast with The Syndicate, Yakuza, The Mafia, The Mafiya, London Gangster.
In the second season of Ghost in the Shell: Stand Alone Complex, they show up in an episode where Mokoto visits the territory primarily occupied by (generally Korean and Chinese) refugees. They have a dignified Don, but the lower ranked gangsters are all common thugs.
In Mayu Shinjo's Haou Airen, an Ordinary High-School Student named Kurumi Akino saves the life of a handsome stranger and nurses him back to health. It turns out he's Uon Hakuron (a.k.a. Li Shen Wong), a dangerous and sexy Triad leader, and few after said incident she's kidnapped from school and taken to Hong Kong...
In Judge Dredd, the judicial system of Hong Tong (the future Hong Kong) has been largely infiltrated and taken over by Triads, much as the Hondo-Cit (Japan) Judges were overtaken by the Yakuza.
The Triads play a prominent role in the Corto Maltese book Corto Maltese in Siberia (Corte sconta detta Arcana), as well as in the Animated Adaptation based on the book, Corto Maltese: La Cour secrète des Arcanes.
New York's Chinatown Tongs are a major force in DMZ, especially due to their cunning leader Wilson.
Sin City mentions Tongs being present in the town but they have yet to appear in the series.
Darcy Parker in Strangers in Paradise supposedly had Triad connections. Since she began her criminal empire in her native Hong Kong, this is not surprising.
The villains in The Shadow Hero are a Tong that has degenerated into a mere criminal gang, although the ending implies that it may regain its honour under a new leader.
Election, and its sequel Triad Election in which the oldest HK Triad kills and maims more of its own members than the rival gang.
A Better Tomorrow. Mark Gor (Big Brother Mark) inspired a generation of Chinese kids to walk around in dusters and sunglasses while chewing on toothpicks. Mark Gor (and every "criminal" that Chow Yun-Fat played afterwards) is a romantic in a cynical world, who steadfastly holds onto notions of brotherhood and honor, and would gladly lay down his life to protect innocent women and children.
Fu Manchu often works with/controls these groups in films which feature him.
The 1985 film Year of the Dragon (based on the novel by Robert Daley, screenplay by Oliver Stone and director Michael Cimino) tells of the struggle between a controversial New York police captain and an ambitious young Triad member, both of whom upset the 'live and let live' status quo between the Triads and the police.
In Kung Fu Hustle, several gangs are causing trouble in Shanghai with the Axe gang being the most powerful one. In fact, the beginning starts with a small gang bullying a police station, only to get eliminated by the Axe gang.
Romeo Must Die has an African American gang and a Chinese gang butting head over waterfront property.
The second and third Rush Hour movies deal with the Triads. Of particular note are the Parisian Triad members who don't even speak Chinese. The first movie has a Chinese gang, but they are working for an Evil Brit.
In Skeleton Key a branch of the Triads called the Big Circle attempts to set up a betting scam at Wimbledon, but Alex uncovers the scam and ruins it. A Big Circle agent later attempts to assassinate Alex in revenge.
In Deadwood, a Tong gang supported by George Hearst wrests control of Celestial Alley from the local strongman Mr. Wu, with the goal of supplying Chinese prostitutes and opium to white residents. Eventually Al Swearengen helps negotiate for Wu to retake control of Celestial Alley and slaughter the new Tongs.
The Doctor Who story "The Talons of Weng-Chiang" has the Tong of the Black Scorpion as Mooks serving their Physical God Weng-Chiang (who turns out to be a psychotic time-traveller from the future who bamboozled them with high-tech tricks).
Tongs were the focus of a couple of episodes of Kung Fu
A really ridiculous episode of Psych depicted a kidnapping related to two rival Triads in Santa Barbara. Yes, two Triads in Santa Barbara.
A group of Tong serves as the main villain in the second episode of BBC's Sherlock though it's referred to as an ancient Chinese crime syndicate rather than a Chinese-American organization a little over a century old ( and, as with the previous episode's villain, it turns out that Moriarty's The Man Behind TheDragon Lady).
An episode of Castle features a tong. This example is unusual in that a character mentions that most tongs are legitimate organizations.
In an episode of Arctic Air the police are looking for a hitman from Vancouver who is trapped in the arctic community when a snowstorm stops all traffic in and out of town. One of the older mechanics starts telling stories about how nasty and deadly Triad assassins are. His stories are mostly nonsense and the hitman is actually Caucasian and working for a biker gang rather than any Chinese crime group.
The mission that qualified Nikita for active duty involved the assassination of Victor Han, a member of the Department of Homeland Security in its early days. In actuality, the assassination was faked in order to remove Han, a triad member, from the intelligence community without pissing off said triad overmuch. Fast forward to the present day, and Nikita lays into a triad's New York operations only to discover Victor Han is in charge.
The Triads are one of the biggest powers in Shadowrun, and effectively have all of Hong Kong in their pockets. The Yakuza are engaged in a vicious rivalry with them in San Francisco.
The Triad Sourcebook, one of the few supplements for Hong Kong Action Theatre, is an invaluable resource on the Triads and their use in Hong Kong action games in general.
A common enemy and occasionally ally in the contemporary juncture of Feng Shui. As with other criminal syndicates in the Feng Shui setting, they're largely controlled by the Ascended.
The Martian Triads are one of the major inner-system crime organisations in the GURPSTranshuman Space setting. While they do the usual organised crime stuff (loansharking, smuggling, protection), the bulk of their income comes from selling restricted and illegal bioroids, and they're known to have at least one Evilutionary Biologist on staff.
Eclipse Phase also has Space Triads, mostly based on the Moon and on non-planetary habitats. They're notable as the only criminal organization that remained racially homogeneous after the Fall, as other groups had to merge when their ranks were decimated. They specialize in stealing and trading "forks," copies of a person's mind.
In Eclipse Phase a few Triads are essentially the only ethnic syndicates to survive the Fall thanks to China's significant presence on Mars beforehand. The few survivors of the Mafia and Yakuza and Cartels coalesced into the Night Cartel.
The Triads and the Tongs have been featured in every 3D Grand Theft Auto game thus far. You only work with them in San Andreas, however, though you get to wipe them out in GTA3.
The DS game Chinatown Wars obviously features them far more heavily than other GTA games. The player is the nephew of a triad leader.
Deus Ex features them from the Hong Kong levels onward.
The prequel Deus Ex: Human Revolution features the Harvesters, a gang in the fictional two-tiered Chinese city called Hengsha, who "harvest" mechanical augmentations from others. Their leader is Tong Si Hung, the father of Tracer Tong from the first and second games.
The Dark Elf mafia in The Elder Scrolls is called Camonna Tong. The (legal) assassins' guild is the Morag Tong — both of these come from Tong being Dunmer for 'Guild' (Morag means 'Forester'. What Camonna means was never explained).
Given their focus on ancestor worship and ability to summon said ancestors' spirits, it's likely that in this game's verse the Tsoo actually came first and that a lot of the Triads were willingly assimilated.
The Bangkok mission set in Mafia Wars has the player choose to ally him or herself with the Triads or the Yakuza, affecting which missions become available.
The John Woo game Stranglehold, in keeping with its cinematic predecessor Hard Boiled, has Tequila going up against two of these along with a Russian crime syndicate.
Rubi of Wet travels to Hong Kong on several of her missions, and thus has to fight these guys several times during the course of the game.
The Triads play a semi-major role in the last 3rd of the plot of Mafia II.
The White Mountain Triad is a minor faction in Alpha Protocol, and its leader, Hong Shi, is a source of intel, missions, and resources during the first half of the Taipei mission hub.
The very first set of levels in Hitman: Codename 47 involve stirring turmoil between the Red Dragon and Blue Lotus Triads by killing key members during negotiation attempts as part of a plan to get close to and assassinate the Red Dragon leader, Lee Hong.
Sleeping Dogs is set in Hong Kong's criminal underbelly, with the protagonist Wei Shen being an undercover cop trying to infiltrate the Sun On Yee gang.
The Getaway features a London branch of the Triads, and it's spin-off "Gangs Of London" has the Water Dragon Triad as one of the five playable factions.
Strider Hiryu confronts a large-scale Chinese Mafia terrorist strike in the first stage of Strider 2.
The criminal Baoliusung Gang from the second Tenchu game.
ASH: The Onyx Eye tong are a crime syndicate and a villainous martial arts school.
The Legend of Korra has the Triple Threat Triad and rival gangs the Agni Kais and Red Monsoons, groups of bending criminals with a large amount of influence in the poorer areas of Republic City.
It's safe to say that Pandabubba from Xiaolin Showdown and his underlings fall under here.
A few Triad members appear in "Sneak Peek", an episode of Batman Beyond, where the Triad leader Jimmy Lin attempts to talk to the DA, and is filmed by journalist Ian Peek.
Time marches on. A "Tong" in Chinese can mean group, organization, association, club, etc. The liklihood of Tongs containing members who speak Chinese (or at least were ethnically Chinese born) is high, but the odds of it being a criminal organization is no higher than an Italian Restaurant today being a Mob front.