My wife and I ran into a situation where one of us played marched to the wall and the other played wildfire assault. I had 3 characters and my wife had four. The question is which card ability happens first? Would my wife save 3 of her four characters then discard one of the remaining 3 or would she discard 1 and thus only have 3 characters so she doesn't have to kill any. What determines the order or does she get to choose which one she wants to resolve first?
How does Wildfire Assault and Marched to the Wall work?
It depends who is first player. From the rules, under First Player, "For any question as to who should perform an act or make a decision first, in the absence of any other direction by card or rules text, the first player does so first, and other players follow in player order."
Whoever played Marched to the Wall (unless you have initiative modifier cards in play) would probably want to be first player, and would then choose the order in order to either save or kill an extra character.
A garett is right, although he sites the wrong passage (the one he sites informs you that the FP has to choose the character he'll march before his opponent's do).
The relevant passage is "Priority of Simultaneous Resolution"
"xxIf the resolution of two or more when revealed
abilities, delayed effects, or forced abilities would
resolve at the same time, the first player decides the
order in which the abilities resolve, regardless of who
controls the cards bearing the conflicting abilities."
Oops - thanks for the correction. I went through the rules too quickly and didn't look at it closely enough. Apologies, and thanks again for catching it.