We were fighting in the block and one of the guard attacked Char. I forget the guard's name, but it said the target it damaged could not deal damage until the start of the environment turn. Char attacks during the start of the environment turn. The way we played it was:
Char was out first so he tries to attack, but can't. The guard was out second so his effect ends now. At the end of the environment turn the guard attacks Char again (he's still the lowest).
That means that basically Char could do nothing until he died (or someone else had lower HP). However, if the guard was in play first and Char was in play second then Char would always attack and the guard did nothing (except damage).