Honestly, the fact that Agent Stone became such an impactful character for the Sonic Movie canon is insane.
We know that Agent Stone was intended to be a throwaway side character, quite literally just an extension and accessoire to Dr Robotnik for him to express his character with. Agent Stone didn’t matter, he was there to enhance your impression of Dr Robotnik and his personality.
I mean look at this, in the first movie, there are clearly other Agent-like characters following Robotnik everywhere he goes. Not military, Agents. Those are ALL supposed to be Robotnik’s agents.
Even if they are not directly under his command, they are „with him“, his entourage for at least the first half of the movie before they all, including Agent Stone, disappear when Robotnik goes off to do his own thing (destroying that hedgehog).
For all we know in the vacuum of the first movie, Agent Stone and Bot never met before the day this movie takes place and Stone just happens to be assigned to personal bodyguard duty on that particular day. The point is that Agent Stone could have just vanished after the first movie and a good chunk of the general audience for these movies wouldn’t have minded at all.
But Jim Carrey was like „Hey, Jeff, I like this guy, he’s a great counterweight for my character, I think we should expand his role.“ and a few of us from the audience said „Hey, Jeff, we like that fruity assistant guy, we think he and Robotnik should kiss.“ and Jeff said „I agree“. And now Agent Stone is Robotnik’s only real friend and he got his own action figure.