Rivalry Arena is a twist to Redemption Island from Survivor: Bingo vs. Suitman which forces eliminated castaways to duel an assigned "rival" before they can pass through to Redemption. Failure results in them being ousted before they get a chance to duel the other voted out castaways.
At the first Immunity Challenge of the season, with an adjoining Double Tribal Council, the castaways compete in an Individual Immunity Challenge. The position each castaway comes in that challenge dictates the order in which each castaway picks their chosen "rival" for the arena, with full knowledge that they'll have to face-off against this person if they get voted out for their survival in the game. Upon being voted out, the unlucky castaway and their elected "rival" will duel. If the eliminee is successful, they continue to Redemption Island in hopes of winning the duels and returning to the game. However, failure means they are automatically eliminated from the game permanently.