13 Jul 2016
If you discard a card with {X} in its mana cost, X is considered to be 0.
13 Jul 2016
If you copy Nahiri's Wrath, it has the same number of targets and deals the same amount of damage as the original spell.
13 Jul 2016
The damage is not divided. Nahiri's Wrath will deal that much damage to each target.
13 Jul 2016
You can't target the same creature or planeswalker multiple times to deal more damage to it.
13 Jul 2016
If you cast Nahiri's Wrath without paying its mana cost, you'll still choose a value for X and discard X cards.
13 Jul 2016
Nahiri's Wrath adds the mana values of the discarded cards in whatever zone they were put into as a result of being discarded, even if they weren't put into a graveyard (due to madness, for example) or are no longer in that zone.