Final answer:
The passages describe elements of the hero's journey, including 'Crossing the Threshold' and 'The Road of Trials', as the heroes face new worlds and daunting challenges.
Step-by-step explanation:
The element of the hero's journey depicted in the given passages relates to various stages of Joseph Campbell's model. For example, in the ancient Korean novel, the character's discovery of a hidden society after opening a stone door could signify the 'Crossing the Threshold' stage, where the hero moves into a new, unknown world. Similarly, Lucius' journey through the elements could relate to 'The Road of Trials', a series of tests the hero must endure. And the narrative from Euripides about becoming an initiate could depict 'Initiation' where a hero gains new knowledge or power.