TV-Series
Description
Guru Clef, often referred to simply as Clef, is the chief sorcerer of the land of Cephiro and a pivotal figure in the events surrounding the Magic Knights. Despite his youthful appearance as a young boy with light purple hair and striking blue eyes, Clef is actually 745 years old. This youthful form is a conscious choice, as the inhabitants of Cephiro can will themselves to look any age they desire. He typically wears elaborate white robes, a distinctive headpiece adorned with blue gems and a central horn, and carries a large magical staff topped with blue and purple gemstones, which he uses to channel his spells.

Clef embodies a complex blend of wisdom, immense power, and a surprisingly short temper. Having lived for centuries and served as the personal attendant and advisor to Princess Emeraude, the Pillar of Cephiro, he possesses a deep, pragmatic understanding of his world's most painful truths. He is generally calm and thoughtful but can become easily irritated by immaturity or disrespect, once striking the knight Umi Ryuzaki with his staff after she pulled on his robes and dismissed him as a child. Underneath his occasionally gruff exterior, he is kind-hearted and deeply selfless, driven by a profound sense of duty and guilt. His primary motivation is the protection of Cephiro and its people, a goal he pursues even when it requires making impossible choices. He carries a heavy burden of guilt for not revealing the full, tragic purpose of the Magic Knights' summoning—to kill the very princess who called them—believing he was responsible for involving them in a painful fate they did not understand.

In the story, Clef is the first person the three Magic Knights meet upon arriving in Cephiro. Princess Emeraude tasked him with guiding them even before their arrival, a duty he reluctantly accepts. He is responsible for awakening their latent magical abilities and teaching them their first spells, taking a particular liking to Hikaru Shidou for her genuine eagerness. Early in the first season, he is ambushed and petrified into stone by Zagato, the High Priest and his former student, who seeks to prevent him from aiding the knights. Even in his petrified state, Clef's magic is powerful enough to resist the spell partially, allowing him to communicate with the knights through the creature Mokona and continue to guide and teach them from afar. After Zagato's death and the subsequent death of Princess Emeraude, Clef is freed. In the second season, as Cephiro begins to crumble without a Pillar, he uses his immense willpower alongside other magicians to create a massive protective castle for all the inhabitants. He leads the nation as they search for a new Pillar, helping the Magic Knights in their battles against invading forces from other worlds.

Clef's key relationships are central to the tragedy of the story. He was the teacher of Zagato, Lantis, and Alcyone, and his deep disappointment in their betrayals weighs heavily on him. His loyalty to Princess Emeraude was absolute; he was one of the few to know of her forbidden love for Zagato and pleaded with her not to summon the Magic Knights, knowing it would mean her death. This loss marks him deeply. He also shares a professional relationship with the weaponsmith Presea, who is said to harbor feelings for him, though he remains oblivious. Over the course of the series, Clef undergoes significant development. He evolves from a secretive, pragmatic guardian who feels he must bear the burden of the truth alone to someone who openly admits his failings and apologizes to those he wronged. His internal conflict over the Pillar system, which demands the sacrifice of one individual's happiness for the good of all, leads him to question the very foundations of his world. In the end, his arc culminates in supporting a new future where such a system is abolished, showing a willingness to change rather than simply preserve the old ways.

As the most powerful magician in Cephiro, Clef’s abilities are vast and varied. He is capable of summoning powerful lightning bolts and creating impenetrable barriers, as well as large-scale feats like constructing a castle through sheer willpower or keeping a collapsing city intact for extended periods. His signature ability is to bestow magic upon others, though he later clarifies that his spell only awakens the magic that lies dormant within a person. He can communicate telepathically over great distances, often using Mokona as a medium. He is also a master summoner, capable of calling upon creatures like a giant flying fish named Fyula to transport the Magic Knights. His magical prowess is such that, even after being turned to stone, he retained enough power to act as a guide and mentor, proving his will and magical strength are nearly unsurpassed in Cephiro.