My friend and I played a game recently where he had Balon in play (who has stealth) and I had Robb Stark with a bunch of direwolf attachments including the greywind and shaggydawg (I think). In any case it was the versions which both reduce power and eat characters

My opponent attached and bypassed Rob with stealth.

Even though I cannot have Robb declared as a defender can I still use the abilities on the direwolf attachments?

i.e. - do you need to be participating in a challenge to use a "challenge" ability found on a card in play?

Thanks,

Stu

"Challenge" at the beginning of an ability tells you which phase you can use the effect in. It does not require the character to be participating in a challenge to use it. The text of the ability itself might say "while participating," but there is no general requirement that "Challenge" effects can only be used by participating characters. (After all they appear on locations and events, too, which will never be able to participate.)