What happens if I chose military claim for Calm Over Westeros and my opponent uses Seastone Chair? You reduced your opponent's normal claim, but Seastone Chair replaces the 'normal' claim with killing the character he chooses. So essentially, Seastone Chair trumps Calm Over Westeros.
- Vengeance for Elia treats the player satisfying claim as if he or she were the defending player (and the only defending player, because of the word “the") at the precise moment that claim is satisfied, for the purpose of satisfying claim only. This scope allows for effects that modify claim while you are the defending player, and serves as a triggering condition for "after you satisfy claim as the defending player," but that's about it. For example, if you have Calm revealed, attack in the chosen challenge type, and have claim redirected at you with Vengeance for Elia, claim will be modified by Calm and reduced by 1. If you attack an opponent who has Calm revealed and he or she plays Vengeance for Elia, claim will NOT be reduced when it's redirected.
Rephrasing: I have Calm Over Westeros set to military, I attack in military and win, opponent plays Vengeance for Elia, my own claim is reduced when applied to me (so mil claim 0). — mplain 230