I was re-reading it just now and it dawned on me all of a sudden (pardon if this was brought up before or it happens that my interpretation is wrong):

You can win a challenge as a defender and you must still satisfy the claim along with all other opponents (including the attacker).
I think the card could have been better phrased:

"After you win a challenge as an attacker in which you control Melee Champion as a participant, each opponent (in addition to the defending player) must also fulfill the claim of that challenge."

ALSO

"House X Only"
where House X is the house that won the pertinent storyline league.

Ruvion said:

"After you win a challenge in which Melee Champion participated as the attacker, each opponent (in addition to the defending player) must also fulfill the claim of that challenge."

Remembering that "you" or "your" on a card always refers to that card's controller and that the use of a card's name in it's own text is always self-referential, how do "you" win a challenge as a defender in which the Melee Champion you control participated as an attacker? Without a jumping ability like Greatjon Umber's, you really can't win a challenge as the defending player in which you control characters that are attacking. So I don't think the situation you refer to is ever going to happen.

So what is up with this card? going on 2 years since that article, did the storyline stuff get axed?

I had glossed over the "you" implication...chalk it up to a late night misread?

@Darksbane: the stuff from the first Storyline League got published (or unpublished as the case may be) so I hope we will see the Melee Champion in due time?

If that card actually got printed, in a melee game, I'll be running three of him, and as many cards as I can that can give him a power icon.....