Final answer:
The term that describes a protagonist who is center stage but lacks traditional hero qualities is an 'anti-hero.' Anti-heroes like Deadpool elicit sympathy despite not adhering to classic heroism, differing from antagonists who oppose them.
Step-by-step explanation:
The term being described is an anti-hero, which refers to a type of protagonist who does not possess the traditional attributes of a hero. An anti-hero may lack conventional heroism and is often flawed or has dubious morals, yet they command the center stage of the story. Deadpool is an example of an anti-hero who, despite his questionable behavior and methods, earns the audience's sympathy. Contrarily, the antagonist plays the opposing force to the hero or protagonist, creating conflict within the story. While protagonists such as Superman fit the traditional hero archetype, anti-heroes are increasingly popular in modern storytelling as they provide a complex, layered approach to character development. It is important to note that not every protagonist is a hero, as demonstrated in works like John Milton's Paradise Lost, where the protagonist is Satan.