Who was the first superhero to popularize having a sidekick?

Imagine a world where superheroes flew solo, their clever quips echoing unanswered through the urban canyons. It was a simpler time when caped crusaders could monologue without interruption and villains didn't have to worry about surprise attacks from pint-sized partners.

But then, like a cosmic ray striking a lab rat, everything changed. Suddenly, superheroes craved more than just saving the day – they wanted someone to high-five afterward. The solo act was out, and dynamic duos were in. Some masked marvel looked in the mirror and thought, "You know what this outfit needs? A mini-me."

And just like that, the paradigm shifted. Heroes began basking in post-victory glow, realizing what was missing wasn't the key to the city, but an adoring sidekick with wide eyes and a cannonball of questions. This change rocked the superhero world harder than an alien invasion. Brooding alone on gargoyles? Out. Mentorship, banter, and coordinated costumes? In.

Which superhero first popularized having a sidekick?