Complex sentence: It is said that the Sheikah people were fascinated by a search for truth as they created the Mask of Truth (sold by the happy mask salesmen of castle town in "Ocarina of Time").
Split into simpler sentences: It is said that the Sheikah people were fascinated by a search for truth. They were also the creators of the mask of truth (sold by the happy mask salesmen of castle town in "Ocarina of Time").