The other night in a game I had my dwarven Grudge Thrower and enough resources and characters to trigger it's effect 3 times (Spend a resource and sacrifice a character to give all attacking or defending units a (power) icon). I triggered it the first time, then my opponent played a tactic card that destroyed the Thrower "in response" to the GT being used, then "in response" I triggered the GT again. I'm pretty sure this is allowed, but the question got hung-up on whether I could trigger the GT a third time, "in response" to my using it the second time. Thus, I would have gotten 2 uses of the GT, then it would have been destroyed, and then not on the board for the last use.

My opponent (and a few other players) argued that I shouldn't be able to use the GT the third time, as I was responding to my own action. Although being able to trigger the GT twice successfully would have won me the game (I eventually lost), I decided to rule in favor of my opponent, and to check later for how the action/reponse window works (from what I've read so far, I'm not the only one who finds the description a little vague).

How would this work -- could I keep triggereing a card (any card, not just the Grudge Thrower) as long as I can meet the play requirements as "in response" actions? Is there a point where the action/response chain ends and resolves outside of changing phases? Was my opponent correct?

"Once an effect has been paid for, that effect is a part
of the action chain, and the effect resolves even if the
source of the effect is removed from play."

The first use of grudge thrower ability still works even if he destroys it in response. You used the ability second time in response to his card destroying it thus gaining second power icons to your forces. Actually to my knowledge the rulebook doesn't forbid playing actions in response to your own actions so you could've used it third time. Now waiting for someone to correct me...

As of right now there is no restriction on you responding to your own action even with the same card. In AGoT we have the one response per card per trigger rule, but that rule does not exist in this game at this time. The FAQ may change that (and probably should IMO).

You'll notice Lafi quoted the relevant section of the rulebook about the more important unasked question, "What could I have done to win?" The answer being exactly what you did. You did win the game sir. Congratulations. Once the effect has been added to the action chain it must be canceled or have its target removed or otherwise made invalid in order to not resolve, even if the card that placed the effect in the action chain is removed from play. So the first trigger was valid and was going to resolve since it created the action chain, and the second one was valid since it was a response to your opponents response and part of the action chain.

This means even if the FAQ decides there is one response per card per trigger, and you cannot respond with a card to that same cards action, you had two valid triggers since one was an action and the second a response to your opponents response.

As a follow-up question on this card, I was messing around wiht Dwarves tonight while teaching a friend how to play. I was interpreting the card text to allow me to spend 1 resource and sacrifice a unit (mine or his) to get the bonus to my other units. Does everyone else agree that the thrower can sacrifice other player's units to trigger its effect?

A sacrifice does always only mean OWN units. Otherwise it wouldn't be a sacrifice.

So no, you can't use your opponents units to gain that bonus.

1. The WHI stack works like the old Magic stack. You can play tactics as long as both players don't pass on playing them consecutively. So it would be possible for you to play as many actions as you like , as long as you can afford to pay their costs.

2. A sacrifice always means your own cards. Your opponent's cards would be destroyed rather than sacrificed . So always look out for the wording to get the answer.