Sorry, I’m not near the card to name it or quote it directly, but you should get tit from the title of this post. How does it work? Can it deal damage every hero turn, environment turn and villain turn, as long as I have cards to discard? Or is it talking about each of that hero’s turns?
Bonus question: How does damage of two different types handle bonus damage? The same hero has the power of dealing 1 point of one damage and then 1 point of another type. Would the hero’s power that increases damage by one make each instance of damage increase for a total of 2 + 2, or is it 1 + 1 + 1? If it is the latter, which damage type gets the plus?
The second question has already been answered previously. It’s easiest to think of it as dealing two separate attacks. Thus, you are dealing one radiant damage (which is then altered by any damage modifiers) and then dealing one melee damage (again, altered by any damage modifiers). So, a +1 would affect both damages, while a -1 would also affect both damages.
As far as the first, the card reads “at the start of each turn,” thus it includes the villain and environment turn as well.
For the first question, if it says every turn, it means EVERY TURN. That does include villain and environment turns. Assuming you’re talking about Fanatic’s Divine Focus, you have the option to discard a card to deal damage on every turn, all the way around the table, then choose to take the damage and keep it going another round.