It's the masks that they have on their face.>>6427298
It's a competition between 8 contestants who go against each other in a bracket.
After each "match" there is a segment where the judges praise them, people try to guess who they are, and then it goes to voting. The judges and audience vote on who continues.
The winner keeps his mask, the loser is unmasked.
At the end of the episode the best one out of those 8 goes against the standing king.