I'm not sure that whether the individual believes there is a reward is relevant.
Example: atheist terrorists -- atheistic suicide bomber, say -- would be heroic because they don't believe there is a reward?
Example: atheist terrorists -- atheistic suicide bomber, say -- would be heroic because they don't believe there is a reward?
On a related note, would you consider someone like Ozymandias (https://en.wikipedia.org/wiki/Ozymandias_(comics)) a hero?