Elias Ainsworth is the central male figure in the story, a non-human mage whose existence bridges the gap between the mundane world and the realm of myth. His true origin is deliberately obscure, as his earliest memories consist only of wandering alone in a forest and collapsing during a snowstorm. He was discovered and nursed back to health by Lindel, a dragon-riding mage, and was given the name Elias Ainsworth by Lindel’s own master, Rahab. This marks the beginning of his long life, which spans centuries, as he traveled with Lindel, learned the craft of magic, and tended to reindeer before eventually settling in Britain.

Physically, Elias is most recognizable in his default form, which is a towering, humanoid figure with a head resembling an animal skull, complete with curving horns. His eye sockets glow from within, and beneath his formal attire of a dark robe, vest, and white gloves, his neck reveals dark, almost purple skin. He possesses a significant ability to shapeshift, able to adopt fully human forms or even animals, but maintaining these illusions requires conscious effort and they often fail when he is under emotional distress. In these moments of rage or intense protectiveness, his true form emerges, a much more bestial and skeletal creature adorned with thorns and tattered, cloak-like appendages.

His personality is a complex blend of refined politeness and fundamental otherness. Having lived for centuries, he can understand human emotions intellectually, but he is incapable of feeling them naturally. This detachment leads him to observe and mimic human behavior to fit in, adopting the mannerisms of a gentleman, though he often struggles with social nuances and emotional responses that would come instinctively to a person. This lack of empathy manifests in a peculiar childlike quality; his emotional responses can be primal and direct, and when frustrated or jealous, he is prone to throwing tantrums or acting possessively. He is generally reclusive, preferring the company of only a small circle of acquaintances, and he notably dislikes children, who are often able to see past his human guise to the monstrous being beneath.

Elias’s primary motivation, which sets the story in motion, is a deeply personal one: a desire to understand human emotions. He believes that by taking a human apprentice and bride, he might learn to feel as humans do. This leads him to an auction in London where he purchases a young woman named Chise Hatori, a rare Sleigh Beggy with immense magical potential and a tragically short lifespan. He brings her to his home in the English countryside, not only to be his apprentice in magic but also to be his future wife, establishing a unique and complex relationship that is part teacher, part protector, and part partner. His role in the story is defined by this bond; he acts as Chise’s guide into the world of magic, protecting her from supernatural dangers while also wrestling with the very human emotional challenges their relationship brings.

His key relationships are central to his development. His bond with Chise is the most significant, as she is the first person to fully accept him, even after witnessing his monstrous true form and his predatory nature, which includes a past where he may have consumed humans. Through Chise, he begins to experience loneliness, jealousy, and a desperate fear of abandonment, feelings that are completely new to him. His relationship with his former mentor, Lindel, is also important, representing a connection to his own past and a source of wisdom that he rarely shares. He maintains a working relationship with the Church and has allies like the priest Simon and the craft-mage Angelica, all of whom accept his unusual nature. He is also on familiar terms with the fairy rulers Titania and Oberon, who regard him with a kind of detached curiosity.

Throughout the narrative, Elias undergoes significant development, moving from a being of pure emotional ignorance to one who is actively struggling to become more human. Early on, his attempts to understand attachment are clumsy and sometimes morally ambiguous, such as when he plans to sacrifice a child to save Chise from a deadly curse, an act driven by possessive desperation rather than malice. This event causes a major rift in his relationship with Chise, forcing him to confront the flaws in his thinking. He learns that he cannot simply keep her safe through any means and that genuine partnership requires mutual respect and understanding. He later accepts a position as a professor at a magical college, a step that forces him to further integrate into human society and control his more monstrous instincts. This journey is a constant struggle between his fundamental nature as a predatory being and a growing, heartfelt desire for connection.

In terms of abilities, Elias is an immensely powerful and renowned mage, earning him epithets like the Thorn Mage and the Rending-Eating Castle. He specializes in shadow magic, which he uses for teleportation, creating solid constructs, and imprisoning his targets. He is also capable of potent destructive magic, summoning thorns or spears from darkness. Beyond these, he has several unique talents, including the ability to manipulate memories, possess other bodies, and split his consciousness into a separate, canine-like form that retains his mind but with diminished power. His physical strength is also considerable, allowing him to tear apart supernatural creatures with ease. Despite his vast power, he has notable weaknesses; his human glamour fails under emotional strain, and he is notably inept at delicate spells like purification, which would require a level of gentle empathy he naturally lacks.