Long story short, Jason Todd, you're ordinary, boring, and unremarkable. But now you have a chance to become a hero.
Do you want to be a hero?
Jason: No.
Countless meteorites fell from the sky, and the entire world turned to dust.
...Now you have another chance to stay alive. Do you want to live?
Jason: ...Let's see.
Jason, from an ordinary world, is approached by the World Monitoring System. It wants him to save worldlines on the verge of collapse because their key characters are missing. The way to do it is simple: play the important roles until their real counterparts return.
Jason: No way. I'm slacking off.
1. Playing Batman
Alfred: The young master hasn't smiled like this in a long time. (Relieved)
Dick: ...It's fine. When I first started using a grappling gun, I couldn't swing across properly either. (No, I didn't!)
Joker: I suggest you take a few mandatory acting classes. (Why do people like you when your acting is so bad!)
Damian: What? You want me to inherit the Batman mantle right now? (Overjoyed) (Sprints away) (Drives the Batmobile off a bridge)
System: Run! The real Batman is back. He'll turn you into a chart!
2. Playing Iron Man
JARVIS: Sir, I recommend taking another IQ test. My data needs updating. (Secretly searching) (How to care for someone with a high IQ who has become stupid)
Captain America: Starting a car without a key is a useful skill. When did you learn that? (Isn't that just car theft?)
Fury: Legally speaking, your signature is valid right now. (Brings over every document that was ever rejected)
HYDRA: Our base was just bought. The new landlord is... Iron Man. (Refuses to pay rent) (Utilities cut off)
System: Wait a moment. Let me settle your accounts before I go. I hope the Cosmic Economic Oversight Bureau doesn't arrest me. (Where did that one cent go?) (Jason: It's only one cent. I'll pay it myself.) (No!!!)
3. Playing Spider-Man
Neighbor: Spider-Man? He's no different from before. (Still spaced out all the time)
Classmate: Peter Parker? He's no different from before. (Still weird as ever)
Flash Thompson: Hey, Peter Parker... Ah! (Gets hit in the head with a basketball)
System: Perfect performance. It cries tears of joy.
*
Later
People from different worldlines: I know he's not the real one, but he has his reasons. He's doing all this to save the world. He's a true hero. (We'll play along!)
Jason: No, I just took some acting lessons.
*
Theme: Experiencing life from many perspectives