Difference between Experience and Heroic ability??

[Karacan]

The numeral experience for a commander is shown while he's in the Hall Of Fame.

Leaders who drop out of the Hall Of Fame retain their heroic ability, leaders who stay in there increase their heroic ability's power. There's only one, though, and you're stuck with it when your scout gets the heroic leadership ability...

National heroes are just very powerful nationspecific commanders that come as a lucky event. The "hero" title is, in their case, more of a flavour text. They gain experience and heroic abilities like everyone else: Through getting into and staying in the Hall Of Fame.

I think a kill is worth roughly two points of experience for calculation of the HoF. Don't know for sure, though.