The special firing depends on that yes. But slash attack come at certain intervals (you can see when each hero is going to strike be the number next to their health bar).
About gems giving enemy mana, here is some discussion about it:
The special firing depends on that yes. But slash attack come at certain intervals (you can see when each hero is going to strike be the number next to their health bar).
About gems giving enemy mana, here is some discussion about it: