Some time later, Garth encountered a band of shark-like merpeople who attacked the hero with a kind of "mystic water." Garth vanished and reappeared in another dimension, where Atlan awaited to train him. Atlan taught Garth to use powers the young Idyllist didn't know he possessed, including elemental powers which allowed him to heat and cool water and create whirlpools, as well as fiery purple blasts of energy from his eyes. Toward the end of his training, Garth was scarred in a ritual, leaving two pronounced scars over his right eye which healed into "tattoos" once he had conquered his inner turmoil. Atlan told Garth that the final part of his training was to complete the ritual that would grant him full access to his ancestral magical power, and thus Garth had to return to Shayeris, in the Hidden Valley.