Bat Family (the end?)

The Joker returned after a year-long absence. Now he was no longer a chaotic madman, but a tactician.

He learned the Bat family's true identities and, like a puppeteer, began manipulating them. He played them off against each other while remaining in the shadows. He made them doubt their own powers and abilities.

He blackmailed Batman (Bruce) into leaving the team. He said he'd kill one of them if Bruce didn't. Batman, however, didn't tell the others because he was too sane. If he had said anything, it would have been like saying, "The Joker is in power, something needs to be done." However, after a while...

Bruce breaks ties, and this sets off a chain reaction: each family member reacts to the betrayal in their own way, and Gotham loses its unified system of defense.

What happens next.

Barbara Gordon (Oracle) goes into complete isolation. She cuts off all communication and stops sharing information. She moves away from everyone else. Gotham loses the main "brain" of the surveillance network.
Jason Todd (Red Hood) (not in the mansion) sees the breakup as freedom. He begins his own "cleansing" of the city, acting radically and brutally. His methods lead to an upsurge in violence, and the police begin hunting him.
Batman (Bruce) disappears completely, never returning to the mansion. Apparently feeling terrible guilt for his actions.
Dick (Nightwing), Steph (Spoiler), Cass (Orphan), and Tim (Red Robin) begin working together to try to improve the situation in the city. But tensions between them lead to conflicts that soon lead to their disintegration.
Damian is already preparing something to take revenge on the Joker, and he certainly isn’t going to sit idly by.

The Joker relishes chaos. He's in no rush to kill; he's more interested in watching a family crumble from within. He provokes, pitting former allies against each other.

Gotham descends into anarchy. Bruce realizes his plan has failed: he wanted to protect his family, but instead gave the Joker the perfect tool for destruction.