The Queen of Thorns' worst nightmare.

and tears

and Doran's Game

Does she stop keywords?

Nevermind. I must be tired or something... It is explained right there in triggered abilities section.

BTW she just smashes with Like Warm Rain. Uncancelable...

How would Cat interact with Tyrion? I'm assuming that if Tyrion initiates, the 2 gold goes off, but if Cat initiates, she blocks it?

As far as I can tell, Catelyn's ability would only stop Tyrion's ability if she was attacking in an Intrigue challenge. If Catelyn is defending, Tyrion on the attacker's side can trigger his ability before Catelyn's controller declares defenders.

Yup.

can someone explain to mean exactly what "while participating in a challenge" means.  is she considered "participating" until the challenge ends at 4.2.6?

Yes. As it says on p. 15 of the FAQ, once a character is participating in a challenge (by being declared as an attacker or defender, or jumping into a challenge with a card effect, a la Jon Snow, for example), they remain "participating" through the resolution of the challenge. The challenge formally stops resolving at 4.2.6.

This means that Catelyn is considered to be participating through the entire resolution of the challenge and therefore stops interrupts and reactions to things like winning/losing the challenge, claim effects, etc.

So basically Catelyn doesn't stop event like Risen from sea ?

So basically Catelyn doesn't stop event like Risen from sea ?

If Catelyn is participating in the challenge where the character died, then she'd prevent an opponent's Risen From the Sea. It's a triggered ability, tirggered by an opponent.

Does Catelyn stop keywords? I thought they were triggered abilities, but looking at their descriptions, the word triggered isn't used.

No, Catelyn doesn't stop keywords.

Can Catelyn stop opponent from playing Dracarys! if she was a participant in the Challenge?

Yes

What about Ambush?

What about Ambush?

She only prevents triggered abilities, so she does not prevent anything that lacks a boldface precursor (e.g. keywords like Ambush or Renown).

So, Catelyn wouldn't effect non-triggered abilities like Robert Baratheon's text as non of has the bold preface that indicates triggered:

• King. Lord.
• Intimidate. Renown.
  Robert Baratheon gets +1 STR for each other kneeling character in play.

Or Balon (core) :

Ironborn. Lord.
Renown.
While Balon Greyjoy is attacking, each defending character with a lower STR than his does not contribute its STR to that challenge.

Those are keywords and constant abilities right?

Right.

She also do not stop The Hound's Forced reaction, because they are not considered triggered by a player but "by the game".

Thanks

Do I understand correctly that she prevents also Treachery? So the only effective counter to her are Nightmares or some other effects which prevents her to enter the challenge in the first place (like stealth, challenge icon removal or kneel)?

She also prevents Ghaston Grey or Rains of Castamere. I think for the price she has, she is one of the best Stark characters. Even First Snow will not get rid of her... she seems even better than the core Tyrion.

Do I understand correctly that she prevents also Treachery? So the only effective counter to her are Nightmares or some other effects which prevents her to enter the challenge in the first place (like stealth, challenge icon removal or kneel)?

 

She also prevents Ghaston Grey or Rains of Castamere. I think for the price she has, she is one of the best Stark characters. Even First Snow will not get rid of her... she seems even better than the core Tyrion.

yes, stops trachery.

she can be stopped with ward also

Do I understand correctly that she prevents also Treachery? So the only effective counter to her are Nightmares or some other effects which prevents her to enter the challenge in the first place (like stealth, challenge icon removal or kneel)?
 
She also prevents Ghaston Grey or Rains of Castamere. I think for the price she has, she is one of the best Stark characters. Even First Snow will not get rid of her... she seems even better than the core Tyrion.