So, my friends had a disagreement about the effect of the wars are won with quills event.

I used the event to make my opponent not be able to attack or defend during power challenges. Now here comes our disagreement. She had Euron's Crow Eye in play, which is immune to events.

My point: The event says that the opponent cannot attack or defend. So no matter if she has characters which are immune to events, she as an opponent can simply not attack or defend in a power challenge.

My friend's point: Since Euron is immune, my friend should still be able to attack or defend with Euron.

Who is correct in this case?

The event limits what the opponent is allowed to do and does not affect any characters specifically, so cards that are "immune to events" and cards that don't have that immunity are not affected by events that specifically restrict a player from performing actions.

Ok, thanks Bomb.

So since the event targets an opponent directly, it doesn't matter if that opponent has characters which are immune to events. Tne player is affected by the event and not his characters.

So in my example, my friend cannot attack or defend in power challenges. Correct?

Correct. It turns out that ALL of your friend's characters are "able" to attack or defend (immune or not), but the event says it is illegal for her to declare them as such.

The "grammatical shorthand" for deciding whether or not immunity protects a card is to look to see if the immune card is the subject of the effect. It sometimes seems counterintuitive because "characters you control cannot be declared as attackers" is blocked by immunity, but "you cannot declare attackers" is not - even though they seem to accomplish the same thing in the end.

Thanks ktom!