Sooo i have another idea but i swear i would continue this one because it even has an end planned already! Let's say that my head loves to make series so i was thinking about the reader being the second biological son of bruce and the youngest in the house but your mother was a meta thief that goes from city to city and is able to control shadows and materialize it but the same power is really dangerous because the shadows could get out of control and kill the user of the powers by either sucking all your energy, just snapping your neck or you could just pass out or something like that since your controlling something that shouldn't be able to be controlled.
But how does reader got in the manor with bruce? Because people found out you had the same powers as your mom and while she was dangerous and they could never dream of kidnapping her, you were just an innocent cutie patootie and they tried a lot but never got it (until a couple years later) and that's when she decided to talk with bruce and you stayed there for your safety you are 2 years younger than damian so when you got there you were ten when you got there and you wanted to be like them even discovered that they were batman and robin but bruce never let you train or even use your powers since they were too dangerous (you were dangerous he made an exception by accepting you a meta) and by the way damian death will take a huge part in the story, but for now this is like explaining the main idea and I'm not explaining the plot