My understanding is that a hero is 1) capable of great feats in a conflict and 2) not aligned with evil. Extreme moral virtue is neither a necessary, nor a sufficient attribute of a hero. You can be a heroic sniper, pilot, swordsman, etc with pure skill, though you can also be heroically courageous or loyal if circumstances allow you to demonstrate such.
My understanding is that a hero is 1) capable of great feats in a conflict and 2) not aligned with evil. Extreme moral virtue is neither a necessary, nor a sufficient attribute of a hero. You can be a heroic sniper, pilot, swordsman, etc with pure skill, though you can also be heroically courageous or loyal if circumstances allow you to demonstrate such.