Gotham of the False People

Gotham is a cursed city.

It's teeming with a kind of creature called an impostor. Though no one knows whether they count as living beings; nobody has studied them.

They've taken over Gotham and imitate the lives of normal people, making Gotham look no different from any other city.

There are normal humans in Gotham too. Everyone in the apartment buildings Wayne built is human. It's hard to tell whether Wayne is keeping them penned up or just doing it for fun.

Some impostors try to get in, but none of them succeed. During the day, a security guard will stop you. At night, a black monster will swallow you whole.

Story settings:

1. The three secret identities have different backgrounds: Bruce Wayne is an impostor tycoon, Matches Malone is an apartment building security guard, and Batman is the monster that comes out at night.

2. The apartment building has only one entrance, no back door, and you must show your ID to enter.

3. All the adopted birds were picked up, in the literal sense, and they're all human.

4. To eliminate impostors, you need a large-caliber flamethrower. (This is how impostors work in this story; I'm not very familiar with them either.)

5. The original villains have been made ordinary. They're just regular office workers living in the apartment building, though people still refer to them by their aliases. For example, Harley Quinn is a psychiatrist here. Harley Quinn isn't her real name, so you can call her that.

6. Humans and impostors live in the same environment, so the humans in Gotham are all careful and law-abiding.

Theme: Seeing is believing