As a high elf, Adrasteius had potential to study as a mage, but he ultimately preferred to go into the priesthood. He spent a great deal of time in Lordaeron and then in Stormwind, learning about the Light from the clergy there. He encouraged other high elves to accompany him, and he spoke frequently of the Light’s blessings when he was among his own people. He served as a combat medic in a number of conflicts, including the First and Second Wars (as well as the Troll wars back on his home soil).
His temperament in his youth was significantly more relaxed than in later years; he was rarely stirred to anger over anything. His self-possession served to keep him peaceful during this years, but after the trauma of the Scourge invasion and the resulting sickness and corruption it brought to his race, his calm turned to indignant rage. Adrasteius continued to know exactly who he was and what he was meant to do—but his gentle nature was irrevocably altered by the suffering he both went through and witnessed.