What does X means on the cards? The amount of resources you decide to pay ? And what else?

Depends what the card. Most of the time it is define on the cards (usually "X is egal to the number of players"). When nothing define the X you can choose any X.

40 minutes ago, Rouxxor said:

Depends what the card. Most of the time it is define on the cards (usually "X is egal to the number of players"). When  nothing define the X you can choose any X.

The rest is good, but the boldfaced part is untrue, no? Like when you Vilya a Stand and Fight off the top of the deck: it doesn't mean you can put into play a 6-cost Beorn in your discard pile.

FAQ 1.40: 'Unless specified by a card effect, or granted player choice, the letter "X" is equal to 0.'

EDIT: The RR has a new additional clause: 'For costs involving the letter X, the value of X is defined by card ability or player choice, after which the amount paid may be modified by effects without altering the functional value of X.'

So what @Rouxxor said is a little more true than I said, specifically in the X cost situation. I don't think this changes the Vilya/Stand and Fight interaction, though, as Vilya ignores costs entirely—this doesn't give you a chance to choose X at all, thus defaulting it to 0.

Interestingly enough, the new RR clause also helps to cover something like Hail of Stones, which says "Exhaust X characters to…" Even though X is not explicitly "granted player choice" in the card text, the clause is a cost involving X and therefore covered by the RR addition. Good job, Caleb!

If a card make you play a card with a X cost without paying it cost (vilya for example), this X is not paid and so is egal to 0. You are right: it worth to be mentioned.

Thank you!

Am I right in thinking that in the case of, say, Stand And Fight ("Choose an ally with a printed cost of X in any player's discard pile. Put that ally into play under your control."), you pay the cost of whichever card you choose from the discard pile?

So if you chose Gandalf then the cost of Stand And Fight would be 5, while if you chose say Veteran Axehand then you would pay 2? In this case the value of X is based on which card you want, rather than how much you'd like to pay .

Exactly, but you cannot Stand and Fight Gandalf because he does not satisfy “can belong to any spher of influence.” It’s silly, but it’s the ruling from a couple years back.

In this case the X is not chosen by the player, it is determine by the card, it is the cost of the ally.

But beware: Gandalf cannot be the one selected because he is neutral. Only an ally who belong to a sphere can be the target of stand and fight. It is not obvious when reading the card but we get more information further by developers.

Ah, I didn't realise that. I guess with Gandalf it's not so much "Stand and Fight", as "Sit down and put your feet up, can I get you a cup of tea?"

Thanks guys!