Cersei Lannister from Lions of Casterly Rock is pretty powerful in joust games... but she seems even more impressive during a melee game; especially if a Master of Whispers title is active.
Master of Whispers:
You may resolve your claim against any number of opponents of your choice.
Cersei Lannister (LOCR):
Reaction: After 1 or more cards are discarded from an opponent's hand, if you do not support that player, Cersei Lannister gains 1 power. (Limit 3 times per round.)
What happens if the Master of Whispers decides to resolve his claim against 3 opponents (none of them being supported by Cersei's owner) ?
Does Cersei get 3 powers (because a card has been discared in three different opponent's hand) ?
Does Cersei get 1 power (because only one reaction window has opened) ?