[Nick_K]

They are random events. Sometimes when you get a good random event you'll get some gold, sometimes you'll find some gems, occasionally you get a commander...

So, if you want this sort of thing more often then take luck scale. Turmoil would also help.

This sort of positive event often has minimum scales. You might never see them if you had an unluck scale. Taking the luck scale doesn't just increase the percentage of good event and the nubmer of events, it also enables the best ones.
It's certainly possible for other scale requirements or even more exotic ones like terrain type to affect which events are available, but luck is the msot important one. Actually, I'd have thought that a gift from Rhuax would require the heat scale... but I seem to be wrong there!

I believe that your national heros are dealt with by a different system (still based on luck) and aren't events per se.

The Rhuax thing sounds new to Dom3.
In Dom 2 you would sometimes get a fugitive from the hidden kingdom of Elludia (which is a rare magic site, btw). This guy is an ethereal human assassin. The event is also in Dom3 - I've had it in the demo.

You could also rescue a lore master who was trapped in a cave.

Actually, I can't think of any others. They're really cool events though. The commanders aren't a big deal really, but they add a lot of flavour to the game.