Some may have already asked this...my apologies if that's the case. Which claim does Red Vengeance use when it goes off? Does it use the claim from the winner of the challenge (who effectively must satisfy claim to his own plot card) or does it use the opponent's? If the latter, which opponent's plot card is used in multi?
Assuming it's the former, this means that if I play Red Vengeance after my opponent wins a power challenge, I cancel his taking my power but he then takes power from himself...giving himself power in return, so there's zero change in power (other than possibly a power for unopposed). So I would not get any power from his house card, right?