Nahiris Wrath adds the converted mana costs of the discarded cards in whatever zone they were put into as a result of being discarded, even if they werent put into a graveyard (due to madness, for example) or are no longer in that zone
Just remember that they need to agree to it, so ask nicely
Charge counters - One of the themes of the block, several artifacts in Darksteel functioned by accumulating these counters, which players could then spend for various effects
Codebreaker in contrast is primarily played on 2 or on 3 while paired with a non-creature spell to trigger prowess
There is a risk that this may happen, but if your entry point is low enough then at least you wont feel so awful if you have to go this route
The app is free and helps you track your matches, learn about new winning meta decks, and gives you advice during your drafts