4 teams of 10 competed in this season of The Challenge. The teams were formed based on what mainline season of The Challenge a contestant debuted on: those who debuted during the first ten seasons (Road Rules: All Stars through The Inferno II) were placed in Era I; those who debuted between the eleventh and twentieth seasons (The Gauntlet 2 through Cutthroat) made up Era II; those who debuted between the twenty-first and thirtieth seasons (Rivals through XXX: Dirty 30) made up Era III; and those who debuted between the thirty-first and thirty-ninth seasons (Vendettas through Battle for a New Champion) made up Era IV.