History Film / TheInfernalAffairsTrilogy

** Yan was an illegitimate son of Ngai Kwun, a triad boss and father of Ngai Wing-hau. Despite being estranged, Yan's tie to him almost got him expelled from the police academy for real until Wong offer Yan a second chance.

** Yan was a illegitimate son of Ngai Kwun, a triad boss. Despite being estranged, Yan's tie to him almost got him expelled from the police academy for real until Wong offer Yan a second chance.

** Yan's was the illegitimate son of Ngai Kwun, a triad boss. Despite being estranged, Yan's tie to him almost got him expelled from the police academy for real until Wong offer Yan a second chance.

* NoGoodDeedGoesUnpunished: Invoked by the story of Wong told to Sam in second film, where he tried to stop a gang fight as a junior cop with his partner. His partner was mortally wounded by a gangster and Wong wounded and arrested assailant in return. Wong encountered the said gangster a two years later, boozing with Ngai's gang members, as if he faced no consequences for his crime. Wong remarked the incident with a fitting proverb while voiced his regret for not emptying his gun in the gangster's face.

* DirtyCop: Ming and [[spoiler: Billy] as they're both Sam's mole in police force. Yeung was suspected to be one of this due to his tactics and his connection with Shen, a mainland gangster. Turns out [[spoiler: Shen is an undercover cop working for the mainland government and is cooperating with Yeung to expose Ming's real identity.]]

%%* DetectiveMole: Ming.
%%* DirtyCop

* SurvivorGuilt: Ming undergoes this following the events of the first film.

** While filling out their personal information, Keung asked Yan regarding the the second letter of the word ''bodyguard'' in Chinese. Yan attempted to correct him, only to made a mistake with the radical. Doubles as a funny moment.

* BecomingTheMask: Downplayed with Yan, as he was struggling to keep himself from becoming his own mask. Zig-zagged with Ming, who wants to embrace his identity as a cop, [[spoiler: even if it means indirectly causing a the death of Wong and Yan and the killings of Sam and Billy to cover his past. ]]

%%* BecomingTheMask

* HiredToHuntYourself: Both Yan and Ming are ordered by their superiors (Wong and Sam respectively) to sniff out the mole, while themselves being each other's targets.

* SurvivorGuilt: Ming undergoes this following the events of the first film, which also [[spoiler: drove him insane.]]

%%* HiredToHuntYourself: Both Yan and Ming in the first film.

* SurvivorGuilt: Ming undergoes this following the events of the first film.

* ChekhovsGun: The [[spoiler:envelope]] handed by Sam to Ming, Yan recognized it as it he left his handwriting on it when he tried to correct Keung.

* ChekhovsGun: The [[spoiler:envelope]] given from Sam to Ming, Yan recognized it as it has his handwriting on it.

%%* ChekhovsGun: In the first film, [[spoiler: the envelope that contains the personal information of Sam's subordinate

** When filling out their personal information, Keung asked Yan regarding the the second letter of the word ''bodyguard'' in Chinese. Yan attempted to correct him, only to made a mistake with the radical.

** When Wong was giving a watch to Yan, he noted a pinhole camera was located at the number 5, reflecting Yan's birthday and his status as an undercover. [[note]]'''二五仔''' was the term in question, which means snitch in English. This slang is only used in Cantonese language.

** When Wong was giving Yan a watch, he noted a pinhole camera was located at the number 5, reflecting Yan's birthday and his status as an undercover.

%%* AffablyEvil: Sam, mostly.

* HeroicBSOD: In the first film, Yan experienced one [[spoiler: after witnessing Wong fell on the taxi he just got off.]]
%%* HiddenWire

* ShootTheHostageTaker: [[spoiler: Billy shot Yan in the head while holding Ming at the gunpoint, before Billy revealed himself as another Sam's mole to Ming.]]

* ShootTheHostageTaker: [[spoiler: Yan gets shot by Billy in the head before he reveals himself as another triad mole to Ming.]]

* DestinationDefenestration: [[spoiler: Superintendent Wong gets thrown off the rooftop by Sam's goon after he refused to compromise Yan's identity.]]

* ThePurge: Ngai's massacre of the rival triad bosses in the second film, [[spoiler: and Ngai's family near the end of the movie.]]