Just throwing this at a wall and hoping someone picks this up but...
I have been listening to "Die your Daughter" by Susannah Joffe on repeat, and I keep imagining Bruce Wayne having a biological daughter where they were super close when she was in elementary through highschool. But they have a huge falling out in her senior year. So when she is in college, she rarely comes home, and even after she has her degree, she struggles to be around him. Eventually, they find common ground again, but that doesn't last long because one day he receives a call from his daughter her voice is hushed, and she is apologizing for their fight a few years back. He can tell she is panicking. That's when an alarm goes off in the bat cave. Two faces and his men have taken her apartment building hostage. While Bruce is still on the phone with her, he hears a gunshot and her scream and a gurgle of blood. She begins to whisper a mantra of "I'm sorry dad" and " I love you dad." Each time she says it, it sounds weaker and softer. He gets to her too late to do anything except hold her and kiss her forehead while his tears fall on her already pale and bloodless face. But like clock work, Bruce has to save the rest of the apartment complex before he can bury his daughter.
Feel free to pick this up and change what you want. Just tag me so I can read it.