Can values go below zero into negatives? And if so, how do negative values affect the game?
Two potential examples:
1) I play "Bartering", and take an attachment card with a cost of 2 back into my hand. I then play an attachment card with a printed cost of 1. I reduce the printed cost of 1 by 2, which results in a cost of -1.
If there are no negative values in the game, then I simply play the new attachment for free. If there are negative values in the game, do I play the new attachment and add a resource to a Hero's pool? (If a card is paid for by returning the resources required to the resource bank, then a negative cost would be returning -1 resources to the resource bank; I.E. returning a resource to a Hero's pool...?)
2) Marsh Adder is engaged with another player. I use Bard the Bowman's card effect, which gives the target enemy -2 defence when making a Ranged attack. Marsh Adder has a printed defence value of 1, so reducing his defence by 2 defence results in -1 defence.
If there are no negative values in the game, then I simply treat Marsh Adder as if it had 0 defence. If there are negative values in the game, then would I treat Bard the Bowman as having 4 attack (instead of his printed 3 attack) and treat Marsh Adder as having 0 defence? Or would I deal 1 damage to Marsh Adder before I resolve Bard the Bowman's attack, as Marsh Adder's defence is -1?
There are other potential cases, and I suspect it depends on what scenario/deck you are playing, but I'm asking about standing rules not special circumstances.
.... I might also add I am quite proud of myself for asking such a technical question XD