Counter-heroes in duel mode (3.1).

I wouldn't use speed boosts either, as the dwarves will steal them. I would use the runes in a different order – first, stunning, then phasing, when close combat has already begun. However, I was also criticized for using runes in this matchup; I actually won because my opponent didn't destroy the ballista. Repka is in this thread.
Axel defeats Iris. Ultimately, a lot depends on luck – whoever gets more morale and luck will win. But the odds are still in Iris's favor.
Ravenna can also defeat Iris, but not without the opponent's help. When I tested this matchup, I couldn't win against the autobattler...