If you kill the Witch-King, (for example, in Flight to the Ford -3rd of Black Riders expansion), he goes to discard encounter pile. During the game shuffle the encounter deck..., and in one round, you reveal to the staging area (in quest phase) With-King...

Can you use Ring on him? or Frodo can't use his hability with immune cards?

I think that Frodo can't use his ability because the Witch King does not have "When Revealed" on him. But even if I am wrong about that then I agree that the Witch King's static ability applies and Frodo can't use the Ring.

Per his text, Frodo can cancel effects whether or not they are preceded with "When Revealed" (but they do need to be revealed from the encounter deck), but I think the card immunity trumps Frodo's ability, and you couldn't do it.

I would argue that since the encounter card has not hit the table yet, then you would be able to use the ring just fine.

However I don´t need to make that argument since Witch-King reads: "Immune to player cards" and the ring is technically an encounter card. Look at the pretty back

I would argue that since the encounter card has not hit the table yet, then you would be able to use the ring just fine.

However I don´t need to make that argument since Witch-King reads: "Immune to player cards" and the ring is technically an encounter card. Look at the pretty back

But the effect is printed on Frodo, not on the Ring - so it is a "player card effect" and the Witch-king is immune.

Then I shall go back to my original argument, that since it has not hit the table yet, the witch-king´s text is inactive.

Along the same lines that you can use Landroval to save Beorn at the moment he goes out of play, exactly because his text is no longer active.

I agree with Nerdmeister.

But somehow, that means thalin can damage immune enemy that are revealed ?

Hmmn..., good question.

Maybe, because thanks to Thalin, Crows (CORE) not triggers his 'surge'. And 'immune' could be also considered keyword.

PD: if it is so, Thalin will become my favourite heroe

It's definitely "active" since it has been revealed. It hasn't been added to the staging area yet, but once it has been revealed its text is active. Frodo's card text states that the card must have been revealed-- so any 'when revealed' text is active and ready to trigger, barring cancellation.

Hum... that raise another question then... texts are considered to be active while they are in play, but the revealed card is not in play. "When revealed" effect still occures, maybe because of golden rule or whatever, but I see no reason why other texts should be active while revealed and not yet in play.

but the revealed card is not in play.

Where are people getting this idea? Revealed cards are in play. How could they not be?

Official answer:

Frodo's ability is a player card ability, so it cannot be used to target an encounter card that is "immune to player card effects" such as The Witch-king.
The "immune to player card effects" text is active from the moment the card enters play and a card that has been revealed is in play. The Witch-king's text is not active while it is not in play, such as while it is in the encounter deck or discard pile. That means you could use Denethor's ability to move The Witch-king to the bottom of the encounter deck.
Cheers,
Caleb

I have another question now then: can Frodo avoid the Nazgul of Shadow of the Past without triggering his hide test? If 'immunne' is considered to be in play and it is a keyword..., all others keywords also are triggered before Frodo's action, isn't?

"Immune to ... card effects" is a constant effect, instead of a keyword.

but the revealed card is not in play.

Where are people getting this idea? Revealed cards are in play. How could they not be?

From : http://community.fantasyflightgames.com/index.php?showtopic=58753#599863

Q: The impassable bog reads: when revealed, add 1 token to Gollum for every location in the staging area. When this text is triggered, is the just-revealed Bog considered in the staging area? In other words, does the Bog count itself as a location in the staging area?

A: Encounter cards are revealed from the encounter deck, their “When Revealed” effects are resolved, and the card is then placed in the staging area. So the Bog has not yet entered the staging area when its effects resolve.

It does not say if the card is in play or not, but, by the rules :

“In play” refers to cards that have been played or put into play (in a player’s play area), to cards that are waiting in the staging area, to the currently revealed quest card, and to encounter cards that are engaged with that player.

So I deduced the cards was not in play till it reaches the staging area...

Maybe it was wrong from the official answer.

You can't use Thror's Key to immune locations, but because it reads: "after a location is added..."

It is not similar than Frodo and ring. Frodo reads: "card just revealed from encounter set"...

I have another question now then: can Frodo avoid the Nazgul of Shadow of the Past without triggering his hide test? If 'immunne' is considered to be in play and it is a keyword..., all others keywords also are triggered before Frodo's action, isn't?

I think you can because hide is part of the effects listed on the card