This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Death of the Family
Harley Quinn when she's around Joker this time. She has always loved him (before his rumored death, anyway), and she wanted him to love her back. This time he makes it clear that he doesn't love her at all, and locks her up in a cell containing the corpses of many Harley Quinns before her. He considers every single one of them disposable and forgettable. That just makes her escape from him all the more satisfying.
When the Joker "kills" Batman by dosing him with a maddening toxin. Damian is panicking, trying to get his father to stay with him, refusing to fight him, and looking broken as all get out.
In the end, the Jokerwon. Most of Batman's allies no longer trust him, each other, or even themselves anymore; the few who did are Alfred (who will never abandon Bruce) and Damian (who would be murdered indirectly by his own mother shortly afterward). The "Bat-family" is dead.