Black Mask's Gang

Black Mask's Gang was once powerful criminal syndicate before the Christmas Eve Incident and the rise of the Super-Criminals has significantly reduced it to, although still prominent and dangerous, a shadow of it's former self.

Before Arkham Origins Incident
Before the incident on Christmas Eve, Black Mask's men obeyed Sionis due to his overwhelming strength and influence in Gotham with only a few other gangs standing in his way. It wasn't until Joker took over the gang in disguise that Black Mask's goons noticed changes in their boss's personality such as a more light-hearted demeanor,a habit of joking around with his subordinates, and placing bombs under various buildings such as the GCPD's that a few henchmen starting questioning their leader.

Arkham Origins Incident
Black Mask's henchmen were originally working with Black Mask, until the Joker impersonated Black Mask and usurps his gang. When confronted with a new boss, a quarter of Black Mask's men refused to join up. They were soon executed by Joker as he took Black Mask hostage. The former Black Mask's thugs (now Joker thugs) are seen working with the Joker; they end up getting locked up in Blackgate along with the Joker.

Some escaped and later that night are found by Sionis who scares the others into working for him again. When Sionis escaped the Joker's torture room, they were assigned to keep Black Mask's drugs safe until they could be unloaded and sold off. Batman found out about their plan and decided to take Roman down for good. He hunts down and destroys the drug caches on by one. He learns that the final one in Old Gotham. When Batman tries to destroy the collection of drugs at the  Church, he is confronted by the last remnants of the gang and Black Mask himself. The remaining loyal members of Black Mask's gang are defeated by Batman and sent to Blackgate once Batman apprehends Sionis. at the last cache Black Mask arises with some of his best men to confront Batman but are defeated and captured.

Arkham Origins Blackgate Incident
You first see Black Mask henchmen along with Joker and Penguin's men harrassing Catwoman outside the cell blocks. Later Black Mask's men are in the Industrial Building (as well as the sewers if you are trying to get The Joker). After the defeat of Black Mask it's assumed they were apprehended.

Cold Cold, Heart Incident
While Black Mask's men are nowhere to be found during the New Year's Eve incident, it is assumed that they were apprehended and were put in their cells at Blackgate.

Between Arkham Origins Blackgate and Arkham Asylum Incident
During the time between Arkham Origins and Arkham Asylum, Sionis seemed to have lost a large amount of influence due to the number of supervillains taking over the criminal underworld. By this time, the gang members working for Joker abandoned him, rationalizing that they would rather work for a businessman than a psychotic clown. They returned to work for Sionis, albeit with a heavily reduced salary.

Before Arkham City Incident
After the escape of Black Mask from Arkham City, the gang helped their boss destroy TYGER's weapon storages as payback against Hugo Strange for locking them up in the open air penitentiary.

Arkham City Incident
The Black Mask's thugs are no where to be found in Arkham City. It can be presumed that they joined the Joker when he took over Sionis Industries, after their boss was captured, or split amongst the other gangs.

After Arkham City Incident
Black Mask reunited his gang and started again his weapon deals.

Arkham Knight Incident
When Scarecrow threatened to flood the city with extremely volatile fear toxin, Black Mask and his thugs decided to join the mass evacuation. Black Mask's gang realized that many criminals would be taken out and when it was over he could once again become kings of Gotham.

After Arkham Knight Incident
Red Hood attacks Black Mask's gang in order to stop a weapons deal between them and The Penguin's gang. Red Hood kills Black Mask's gang members and Black Mask himself at the end.

Members

 * Black Mask (boss)
 * Tiffany Ambrose (associate)(deceased)
 * Giovanni Luchese (High-level member)(deceased)