Basic Trope: A Double Standard where only superheroes can stay heroes while anyone else who attempts to become one is discouraged from trying/the attempt ends poorly.
Straight: Major Victory is a Flying Brick who protects Domino City. His Love Interest Mary temporarily gains powers of her own and tries to become a hero in her own right, but Major Victory immediately depowers her.
Exaggerated: Major Victory is part of a team known as the Justice Guard. Whenever somebody discovers a new way to gain superpowers, they step in to stop and depower them.
Downplayed: Mary wants to take martial arts lessons so she can defend herself against goons, Major Victory talks her out of it as the Big Bad will just send more goons.
The Justice Guard learned the hard way that being a hero is a hard life style: the average hero has an extremely short lifespan and the call destroys one's personal life.Therefore they try to dissuade others from repeating their mistake and becoming heroes.
Inverted: Major Victory wants to become a Battle Couple with Mary, so he tries to arrange for her to get superpowers and encourages her to become a heroine.
Subverted: When Mary has a super-powering accident, Major Victory welcomes her into the Justice Guard.
Double Subverted: However, he then secretly stages a huge fight to convince her of the dangers, leading her right into a depowering trap.
Parodied: "Sorry, Miss Mary, but we've only got ten chairs for the Justice Guard's big meeting table, and they're all taken already. You'll just have to give up those powers and become an ordinary non-super again. Now hold still."
Zig Zagged: How the Justice Guard reacts to a newly-empowered individual depends on the situation. Major Victory refuses to let people he knows, like Mary or Chase, retain powers for fear of compromising his Secret Identity. Other times, they welcome the newly-empowered into their ranks as young heroes need role models. It comes down more to the Guard's judgement of each individual and the risk versus reward.
Averted: The Justice Guard warmly welcomes anyone who wishes to become a hero into their ranks, providing training, guidance, and offering them the chance to leave if they decide they aren't cut out for the superhero life after all.
Enforced: More heroes mean more (voice) actors and more special effects. The company simply doesn't have the budget so only the core team can be regulars.
Invoked: The government tells the Justice Guard that no new superbeings are allowed. If they want to keep their own powers, they'll need to depower any new heroes (or villains for that matter.)
Defied: Mary becomes a super hero and keeps Major Victory in the dark. He has no idea that "Admiral Triumpant" is his Love Interest wearing a mask.
Major Victory actively squashes anyone else becoming a hero because he's built his self-image around the idea that he's The Only One capable of defending Domino City. He feels next to useless in his civilian identity; being the city's champion makes him feel like he's accomplishing something great with his life. After forcibly depowering Mary one times too many, she calls him out on this, sending him into a Heroic BSOD as he confronts the idea that he's been hurting the city by denying it other defenders all this time.
Major Victory prevents Mary from keeping her powers because he doesn't want her to get herself killed trying to fight crime. She's eventually murdered by a thug whom she could have defeated with ease using any of the powers she'd gained in the past.
Major Victory doesn't want anyone fighting crime without the proper preparation. If some young buck wants to follow in his footsteps then they have to pass his Training from Hell. When he feels they're ready they can join him on patrol but until then they should leave it to him.
Major Victory doesn't want to expose Mary to the dangers of Super Heroing but appreciates that she wants to help. He offers differentnon-combatroles.