Saybil studies at the Royal Academy of Magic in Wenias, hindered by amnesia-induced inability to cast basic spells. This memory loss stems from self-inflicted sealing after witnessing his witch mother’s brutal murder in his preteen years, leaving him emotionally detached and devaluing his own life.

His origins emerge later: he is the son of the sorcerer Thirteen and an unnamed witch, with the Mud-Black Witch Zero as his paternal aunt. His mother fled Thirteen’s scheme to forge a powerful bloodline through his conception. Despite Thirteen sparking the War in Wenias and facing execution, Saybil confronts rather than denies this legacy.

Magically, Saybil wields inherently limitless power, dubbed "Abyss Sorcerer" for its bottomless chasm-like nature. This causes severe instability, making his magic uncontrollable during emotional distress. He can replenish or empower other witches and sorcerers by transferring portions of his boundless energy, though mismanagement risks harming others. After his memories return, he fears accidentally injuring allies while grappling with renewed trauma.

Personality-wise, Saybil evolves from apathy to forming deep bonds. His amnesia and isolation initially rendered him emotionally hollow, but friendships with classmates Hort and Kudo, alongside Professor Loux Krystas’s guidance, foster his understanding of camaraderie and self-worth. He relearns empathy, exemplified by asking Hort to explain love while struggling post-memory recovery. This growth solidifies his resolve to aid victims of magical reduction despite familial burdens.

Post-graduation, he joins Hort and Kudo researching Remnants of Disaster at the Forbidden Library, committing to constructive power use. He reconciles with his identity, addressing Zero affectionately as "Aunt Zero" before departing.

Additional traits include susceptibility to motion sickness and implied anatomical features, though the latter lacks elaboration across sources.