Anybody keeping score of how often I use this? No? Good. Don't start.
Joker does the same thing as Ash / any other Pokémon trainer. Sure, he's capturing demons instead of cute adorable creatures (who are equally demonic mind you), and then he's sending those demons out to battle other demons, and maybe capture those new demons so he can eventually use them to fight even stronger demons.
In case you think Persona ripped off Pokémon, try the other way around. Shin Megami Tensei games have been around since 1987, almost a decade before Red/Green. I'm not sure how similar the early SMT games are to early Pokémon; haven't played either. But the similarity is there.
NOTE TO QUEST AUTHORS: Title does not match instructions. I blame
@joob . Seriously, "he does the exact same thing I do" would imply two characters who, oh I don't know, DO, the same thing. Instructions say "closely resemble" which can (and based on responses, frequently is) be interpreted to mean "look alike." I'm not changing my answer though.