After you claim victory for your tribe, the Ancient Wrestler rises and challenges you for your title. Then you continue to the bonus quest where he, The Ancient Wrestler, asks who claims themselves as Champion of Poptropica, which is the player, and challenges you to battle him in the greatest sport of all, wrestling. After you win, however, he openly admits defeat.
The costume won after winning against the Ancient Wrestler
In the bonus quest he challenges you to protect his title and honor, so he is technically not a villain.