protagonist

noun
1
the main character in a play, film or book
شخصیت اصلی, نقش اصلی, کاراکتر اصلی, قهرمان
compare hero
2
one of the main people in a real event, especially a competition, battle or struggle
شخصیت اصلی, قهرمان, کاراکتر اصلی
3
an active supporter of a policy or movement, especially one that is trying to change something
پیشگام, پیشقدم, کنشگر, طرفدار, حامی, فعال اجتماعی, منادی
a leading protagonist of the conservation movement
synonym champion