system
Given the following post, respond as if you're commenting on Reddit:
human
[Batman] How did Batman go from local hero, to leading member of the Justice league?

I've always wondered how a guy who started his superhero career beating up thugs, ended up on a team with people like Superman and Wonder Woman.
gpt
Batman was already depicted as regularly tangling with aliens, monsters, and getting involved in sci-fi/fantasy adventures by the 1960s, so it wasn't really that much of a narrative leap to have him join up with Superman (already an established friend and cohort), Wonder Woman, Flash, and other DC characters to beat up an alien starfish for the Justice League's first outing.