OVA
Description
Guru Clef is Cephiro's chief sorcerer, wielding immense magical knowledge and authority. Despite his ancient age of 745 years, he maintains the appearance of a young boy with light purple hair, light blue eyes, and fair skin through Cephiro's magic system, consciously "willing" his youthful form. He dresses in elaborate white robes, a diadem featuring aquamarine gems and a central horn, and gold earrings. He brandishes a staff nearly twice his height, topped with blue and purple gemstones, utilizing the blue gem to project spells.

Clef embodies wisdom, mystique, and calm authority, yet possesses a fierce temper when provoked, often waving his staff or striking irritants like Umi after she mocks him. He carries profound guilt for concealing the Magic Knights' true, grim purpose—to kill Princess Emeraude—a moral burden haunting him. Though capable of warmth or humor, he displays minimal interest in romantic affections, remaining unmoved by feelings from Umi or Presea.

His history includes teaching magic to Princess Emeraude, Zagato, Lantis, and Alcyone. Serving as Emeraude's attendant, he appointed Zagato as High Priest and Lantis as Captain of the Guard. Clef discovered Emeraude and Zagato's forbidden love but refrained from intervention, privately questioning if Cephiro's splendor justified the Pillar's sacrifice. When Emeraude resolved to summon the Magic Knights, he objected yet ultimately facilitated her plan, entrusting Mokona to Presea and preparing for the knights' arrival.

In Season 1, Clef meets the Magic Knights, awakens their dormant elemental magic, and teaches Hikaru her first spell, Flame Arrow. He guides them via Mokona's communication gem after Zagato petrifies him in the anime. Later, he confesses his prior knowledge of their destined role: to kill Emeraude so a new Pillar could arise.

During Season 2, following Emeraude's death and Cephiro's collapse, Clef uses magic to create a protective castle for survivors. He apologizes to the knights for withholding the truth and aids their defense against invading forces like Autozam, Chizeta, and Fahren. His guilt intensifies, especially in private talks with Umi where he admits his failures. He nearly dies casting a powerful spell to rescue the knights from Debonair and Nova, surviving only due to Sierra's intervention. Post-crisis, he supports Hikaru's abolition of the Pillar system, assists in rebuilding Autozam, and collaborates with other worlds to establish a "New Cephiro."

In the OVA, Clef travels to Earth instead of the knights being summoned to Cephiro, playing a minor role. His character arc concludes with a commitment to securing Cephiro's future without sacrificial systems, reflecting his evolution from a pragmatic guardian to a proactive reformer.