hero or heroine
“The central character (masculine or feminine) in a work. The character who is the focus of interest” (Source: Harmon & Holman, 246).
A hero traditionally has positive qualities such as high ethical standards, commitment to duty, perseverance, and courage. An antihero possesses negative qualities such as cowardice and dishonesty. Protagonist is a neutral term denoting simply the main character of a work.