Possible Clues:

• Most difficult mountain, but succeeded making the top
• From the South, the highest point is most demanding
• Very strict to make the South very high
• Second mountain's most forbidding?
• Most strict and harsh
• Most dangerous mountain on far side of Andes
• The south of the mountain is the greatest challenge
• Son faces tough challenge — more dangerous than any other
• Small mountain's most difficult
• Gravest