Red Vengeance- Cancel the claim effect of that challenge.
Do I also cancel the renown of the winner?
Is renown part of the claim effect? Red Vengeance.
Renown is a separate effect. Red Vengeance doesn't change who wins the challenge, so the attacker still gets renown and other effects of winning the challenge (and you get effects of losing the challenge, except for claim). If you want to deny your opponent Renown, you have to play Burning on the Sand, so no one wins the challenge.
hencook said:
Red Vengeance- Cancel the claim effect of that challenge.
Do I also cancel the renown of the winner?
No, Renown is awarded in a separate Framework Event. RV is a replacement effect relating to claim only. Since RV doesn't change the result of the challenge (just who has to pay claim), the original winner and loser of the challenge don't change for purposes of other effects. The winner still gets Renown and can trigger any applicable "After you win…" effects--and the Martell player still gets her other applicable "After you lose…" effects.