The Los Santos Triad-Duggan Crime Family War is an massive war that occurs during the events of GTA Online: The Diamond Casino & Resort between The Los Santos Triads led by Tao Cheng and The Duggan Crime Family led by Avery Duggan,
Before the war
Before the war, in 2019 the new leader of the Los Santos Triads Tao Cheng buy the newly open Diamond Casino & Resort, seeing this, Avery Duggan and his Family seek to buy the casino but first want to destroy it to reduce proprety value and make them enable to buy everything at rock bottom price.
Tao Cheng disappear right after meeting the GTA Online Protagonist who were made aware of the current situation of the casino and hired by Agatha Baker the General Manager of the casino to save him from The Lost MC.
Start of the war
Right after saving Tao Cheng from the Lost MC, Agatha ask the assistance of the GTA Online Protagonist to protect the casino from the Duggan Crime Family, Avery paid several Hillbillies to go to the casino to start fight against the security and causing a scene.
The Hillbillies paid by Avery Duggan got repelled, however one of them manage to steal the sport car and run over a group of bikers who just arrival at the casino, still they got repelled and the sport car return back to the Casino.
Soon after this incident, The Duggan Family finally agree to meet Tao Cheng accompagnied by Agatha Baker, his Translator and the Protagonist at the Marlowe Vineyards to discuss the buyout of the Casino, however the meeting goes wrong and Avery Duggan send his henchmens to kill them which trigger the war between them and the Triads.
Middle of the war
After the shootout at the Marlowe Vineyards, Tao Cheng's Uncle decide to go to war against the Duggan Crime Family, by hiring the Protagonist to destroy all of his assets in Los Santos which they manage to do so.
In retaliation Avery send a large amount of mercenaries at the casino to kill Tao and the Casino staff, but his nephew Thornton Duggan arrival at the casino to tell them that he still want to buy the casino but that he and his uncle has a falling out due to the latter's ruthelessness and to warn them about the impending assault on the casino by his uncle's mercenaries, the assault was brutal but got repelled by the security and the Protagonist, after the assault Tao will speak to his uncle about what to do next.
End of the war
After the assault on the casino, Tao's uncle tell them to sell the casino as there's too much "drama" surrounding it because Tao's uncle provided much funding to renovate the casino, neither Baker and Tao can refuse him, as everyone prepare to move their belonging, Thornton arrival at the casino again and make an offer to everyone, he propose to save the casino by buying it from the Cheng Family at full price which will result as a transfer of ownership, however he admit that he won't have this much money until someone kill his uncle which will result Thornton to receive his full inheritance.
After informing by Thornton about his uncle's location, everyone turn their attention to the protagonist for help with a lot of money which they accepted.
They go to La Fuenta Blanca which was previously owned by Martin Madrazo now under the ownership of Avery Duggan and kill all of his bodyguards and mercenaries if they were spotted, which led to Avery to escape by extrac helicopter, his last attempt to escape ultimately failled as he was killed by the Protagonist, handing victory to the Los Santos Triads and saving the Diamond Casino & Resort from the threat of the Duggan Crime Family.