Juggernaut
During the Korean War, an American soldier named Cain Marko hid in a cave to avoid an attack by the enemy. A fellow soldier, his stepbrother Charles Xavier, followed him in to convince him to rejoin the battle and avoid a court-martial (the inevitable result if his actions were to reach the attention of the commanding officers). The learned Xavier recognized that the cave contained the Temple of Cyttorak. Marko saw a ruby, remarking that it appeared to be living. He picked it up, despite Xavier's warning, to read the now famous inscription: "Whosoever touches this gem shall possess the power of the Crimson Bands of Cyttorak! Henceforth, you who read these words, shall become forevermore a human juggernaut!" Cain's transformation began as the Koreans' constant shelling of the cave caused it to collapse. Xavier escaped, but Marko survived due to his new-found powers.
Probably the destruction of the Temple of Cyttorak and the subsequent incapacitation of the Juggernaut served to throw a monkey wrench in the Wager. No other Exemplars would appear until years later, after the Juggernaut had clawed his way through the rubble, made his way to America, and battled the X-Men led by Xavier several times. Also, Marko, unlike the other Exemplars when they were created, did not initially lose his will to his power source, but retained his full individuality.
Read more about this topic: Cyttorak