From the official TR
500.1 An attack must cause a vitality loss of at least 1 or more to your opponent to be considered to have “dealt damage.”
Evil Mist: 0damage
E: If this attack is not blocked, your oponent loses 2 vitality
with the current wording on the TR, it would mean that an unblocked Evil Mist with no damage buff would be considered to have "dealt damage" and go to momentum.
Is that correct or do I lurk the TR too much?