The Truth of the Giants is a Key Item in Xenoblade Chronicles. It is one of the three Giants' items found in the game, the others being the Daring of the Giants and the Heart of the Giants. These three items are required to open the door at Three Sage Summit, and are required for The Giants' Treasures and The Final Giants' Ruins.
To obtain the Truth of the Giants, the following chain of quests from Tephra Cave must be completed: