protagonist
prəˈtaɡ(ə)nɪst/
noun
plural noun: protagonists
the leading character or one of the major characters in a play, film, novel, etc.
"the novel's main protagonist is an American intelligence officer"
the main figure or one of the most prominent figures in a situation.
"in this colonial struggle the main protagonists were Great Britain and France"
synonyms: chief character, central/principal/main/leading character, chief/central/principal/main/leading participant, principal, hero/heroine, leading man/lady, title role, lead, star, (leading/key) player, (leading) figure, leading light
"the very first line of the play is spoken by the protagonist"
antonyms: minor character
an advocate or champion of a particular cause or idea.
"he's a strenuous protagonist of the new agricultural policy"
synonyms: supporter, upholder, adherent, backer, proponent, advocate, promoter, champion, exponent, standard-bearer, torch-bearer, prime mover, moving spirit, mainstay, spokesman/spokeswoman/spokesperson
"the EC is a great protagonist of deregulation"
antonyms: opponent
Nothing there to say a protagonist is necessarily the "good guy".