A commander in the Hall of Shame will have a Red Circle with a Gold Star on the left side when you select Province view or Nation View. (Grey Circle with a Yellow Star is a Level of Experience).
If you select and view the commander (with right-click) you should be able to view his stats and special abilities, including his Hall of Shame ability. (Just right-click on the red circle gold star symbol)
Every commander in the Hall of Fame gets a randomly selected special ability that increases as they sit in the HoF over time.
What I will add is that this ability is truly random and does not relate to the sort of commander he/she is or to how the commander acquired the experience.
For instance, I will often get "heroic battle prowess," which gives increased attack skill, on my magi. (Hand to hand combat where attack skill is useful isn't something my magi usually do.) Usually the ability is something you are able to at least marginally make use of, however. But not all of the abilities are created equal. I remember a time in the demo that an AI prophet who was a level 5 priest got quickness...he was smiting twice a turn!
Another good one is when the fear effect gets to +15-20 or so. Give the guy some really good armour and flying boots (name?)+the horror helmet (name?). Indies will run away fast. Of course you should not try this against undead.
i think thease shoud be changet for total random to some sort of idea
its stupid that mages get attack as they might not even CARRY weapons or even SEE hand to hand combat
or some assasin get awe (or what the hell is that makes him standard) yea yea he get's bonuses to his leader ship score NOOT he is still an assasin and cant command troops... (at least not normally)
and anyway he sneaks in darkness and attacks in the back how can this figure be wort AWE ?