Erial is the central figure in the mortal half of the relationship that defines the film. He is a human boy discovered as a newborn by Maquia, a young Iorph girl who has just escaped the destruction of her own people. Maquia finds the crying infant alone in the forest, his birth parents having been killed, and decides to raise him as her own son, naming him Erial. This act of salvation sets the course for both of their lives.

Erial’s personality is not static; it evolves in a remarkably realistic manner as he ages, directly mirroring the film’s central theme of inevitable change. As a young child, he is affectionate, innocent, and devoted to Maquia, believing her to be his birth mother. He is eager to help her and finds joy in their simple life together. However, as he enters adolescence, his personality shifts dramatically. He becomes distant, irritable, and rebellious, struggling with the unusual circumstances of his family. The fact that Maquia never ages and continues to look like a young girl becomes a source of great social and emotional strain, fueling his teenage angst and resentment. He feels the weight of their secret and the unspoken, strange nature of their bond, which leads him to lash out and eventually pull away from her protection.

Erial’s primary motivation shifts as he grows. In his youth, his unspoken motivation is simply to be with Maquia and to make her proud. However, as a young man, his driving need becomes a desire for independence and a need to forge his own identity, separate from his ageless mother. He seeks to escape the complicated reality of his upbringing and find a normal life, which leads him to leave home and enlist in the army of the Mezarte kingdom to become a soldier. This act of separation is a painful but crucial step in his journey toward adulthood. Later, his motivations settle into the desire for a conventional family of his own, leading him to marry his childhood friend Dita and start his own household.

Erial’s role in the story is to serve as the anchor for the film’s exploration of motherhood, the passage of time, and the pain of loving someone who will outlive you. He is not a hero in a fantasy epic; rather, he is the lens through which the audience sees the human cost of Maquia’s immortality. His entire life, from infancy to old age, becomes the narrative arc that drives the emotional core of the film. While Maquia remains static in appearance, Erial’s journey through adolescence, adulthood, fatherhood, and finally old age is what gives weight to her eternal perspective.

His key relationship is, of course, with his adoptive mother, Maquia. Their bond is the heart of the film, characterized by deep love but also by struggle, miscommunication, and the painful knowledge that they cannot be together forever. As a child, their relationship is one of pure dependence and love. As a teenager, it becomes fraught with tension and resentment, with Erial often feeling smothered by her unchanging and protective nature. As a young adult, their relationship is one of estrangement, as he actively pushes her away to build his own life. Only in his final years, as an old man on his deathbed, does a deep and peaceful reconciliation occur, where he can finally accept her love without any of the previous complications. Another significant relationship is with Dita, a girl from the same farming village of his childhood who was initially jealous of Maquia. Erial eventually marries Dita and has a child with her, representing his successful transition into a normal human life and legacy.

Erial’s development is the most dramatic and tangible in the story. The film uses time skips to trace his entire human lifespan with startling realism. The audience sees him progress from a crying infant, to a cheerful toddler, to a helpful boy, to a distant and moody teenager, to a determined young soldier, to a married man and father, and finally to a wise, elderly man. This full-circle development underscores the film’s meditation on the fleeting nature of human existence. He begins as the abandoned child who needs a mother and ends as the aged parent who is lovingly left behind, having lived a full and complete life.

Unlike the Iorph, Erial possesses no notable supernatural abilities. He is entirely human in every capacity. His strengths are his resilience, his capacity for love, and his ability to grow and change. In his youth, he learns basic survival and farming skills. Later in life, as a soldier, he would have received combat training, but his most significant "ability" is simply his humanity, which allows him to experience the full, beautiful, and tragic arc of a mortal life.