If there are 5 characters on my opponents team, how many times could Black Cat potentially make them re-roll?

Once on each opponents turn. If you were playing a multi game with several friends, she could make them all reroll on their turn once each turn. Her power works every turn not every action, hope that makes sense.

It does make sense thank you. Generally I only play multi player games, but the rules are USUALLY only written for one on one so I was just imagining the 1600 point 2 on 2 we are about to play and thinking how hard it was going to be not to lose track of which characters I made re-roll