What percent of damage am I doing? To keep it simple let’s say my hero does 100% damage to the Target. What does that mean? What am I doing 100% damage of, another words 100% of what is going to be my damage? Would it be a hundred percent of their attacks score or something?
In effect, yes, the damage percentages are based on the attack stat of the hero.
But that somewhat oversimplifies how damage is calculated. If you really want to go down the rabbit hole to understand it, I highly recommend reading through this thread: