Just want to confirm that this combination will work:

It is not Summer and I have 9 power on my house

I have Mace and Joffrey in play and there is another Lord / Lady in play

• I play Valaar and kill all characters
• I trigger Joffrey's response and put 3 power on Joffrey (in Moribund)
• I play Whispers and move the 3 power from Joffrey to Mace (in Morinbund)
• I now have the 12 power that I need to win the game ....

Mace Tyrell (Lord)

If it is not Summer, reduce the amount of power required for each player to win the game by 1 for each power on Mace Tyrell.

Joffrey Baratheon (Lord)

Response: After a Lord or Lady character is killed, Joffrey Baratheon claims 1 power. (Limit 3 times per round.)

Whispers from the Hill

Response: After a character is killed, move up to 3 power from that character to another character controlled by the same player. Then, draw 1 card.

yup.

Just to be a bit of a jerk here, your second bullet point should be "I trigger Joffrey's response 3 separate times, once for each Lord killed by Valar, for a total of 3 power on Joffrey (in moribund)." (You never know when the technicalities will be important....)

This is of course assuming your opponent doesn't have more power than you because they would win as well and then it comes down to first player to decide who wins.

ktom - your point is valid ... I was discussing this last night and someone mentioned that this involved a couple of responses that could be cancelled ... but as you say, each claim of power by Joffrey is a separate response, so I think this is to my benefit as opposed to my opponents

I know Mace can be a double edged sword - but the benefit to me is 6 power whereas my opponents only benefit by 3

If you move 3 power from one of your characters to Mace, the benefit to you is 3 power, the same as for the other players. If Mace claims power, then yes, you benefit twice as much as your opponent.

If you move 3 power from one of your characters to Mace, the benefit to you is 3 power, the same as for the other players. If Mace claims power, then yes, you benefit twice as much as your opponent.

Very true if you just look at just the "Joff => Mace" step. But over the course of the entire combo, his net benefit is indeed 6.

We agree on that: the entire combo gives you 6 and the other players 3. But the extra benefit to you comes entirely from Joffrey.