Chrono is a central figure in the story, a demon who serves as the partner and contracted ally of the exorcist Rosette Christopher. Despite being a demon, an existence typically defined as an enemy by the religious order he works with, Chrono is affiliated with the Magdalene Order as a staff member. His true nature is that of a powerful demon, a member of a rebel faction known as the Sinners who turned against their own kind in Pandemonium, the demon realm. He is known by ominous nicknames such as the Broken Horn and the Hundred Killer, a reference to his fearsome past.

In his sealed form, which is his usual appearance for most of the story, Chrono takes the shape of a boy in his early to mid-teens, appearing slightly shorter than Rosette. He has a gentle, unassuming look with long hair often tied in a braid and slightly pointed ears. This childlike form is a direct result of his lost horns, which are essential organs for demons to absorb astral energy from their surroundings. Without them, he must conserve energy, and this smaller form reduces the drain on his contractor. When he unleashes his full power, he reverts to his true appearance: a tall, slender, handsome young man with a much deeper voice and a completely different costume.

Chrono’s personality is a study in contrasts, blending profound gentleness with a terrifying, barely contained ferocity. On the surface, he is calm, kind, loyal, and somewhat quiet, often serving as the level-headed, responsible foil to Rosette’s impulsive and reckless nature. He cherishes the peaceful life he has found and is deeply protective of those he cares about, showing a shy and docile side, especially around Rosette. However, this mild-mannered demeanor masks a fierce demon of infamous power and rage. When provoked, or if Rosette is in mortal danger, he can lose control and enter a terrifying, mindless rampage, indiscriminately destroying everything in his path. This fear of hurting his friends and being unable to protect them is one of his greatest internal conflicts.

His motivations are deeply tied to his past and his present bond with Rosette. Having been awakened from a long sleep, he seeks to atone for his past sins as a Sinner and protect the new family he has found. He is driven by a desire to stop the machinations of his former comrade, Aion, who was once like a brother to him. At the same time, he is determined to protect Rosette and find her lost brother, Joshua, feeling a profound sense of responsibility for the tragedy that separated them.

In the story’s narrative, Chrono is both the powerhouse and the emotional anchor for Rosette. Their relationship is defined by a contract in which Rosette offers her lifespan as the source of Chrono’s power. This power is sealed within a pocket watch she wears, and each time the seal is released, her life is shortened. Chrono constantly tries to persuade her to find another way, as unleashing his power causes her pain and hastens her death. This internal struggle defines his role: he must balance the need to protect Rosette from external threats with the desire to protect her from the consequences of their own contract. Key relationships include his complex bond with Aion, a fellow Sinner whose goals he opposes; his protective, guilt-ridden connection to Joshua, who now possesses Chrono's own horns; and his unwavering, soul-bound partnership with Rosette, the human who gave him a second chance.

Chrono’s development throughout the series is marked by a gradual opening of his heart. When he first met Rosette and her brother, he was blunt, wary, and emotionally closed off. Through his life with them, particularly due to Rosette’s persistent and warm nature, his personality softened considerably, becoming friendlier and more expressive. He confronts the bloody ghosts of his past, including the event that earned him the name Hundred Killer, and must reconcile his former life as a merciless rebel with the person he wants to become. His ultimate decision to accept Rosette’s contract, despite knowing it would consume her life, was an act born of desperation and a wish to be with her, setting the stage for the story’s bittersweet trajectory.

Chrono possesses a suite of remarkable abilities powered by astral energy. His signature power is the ability to freeze time, a skill intrinsically linked to the horns that were stolen from him and later grafted onto Joshua. In his true form, his demonic power is immense, granting him superhuman strength, speed, and destructive capabilities far beyond normal demons. The contract system itself is a notable ability; by consuming the soul or lifespan of a human contractor, a hornless demon like Chrono can access his full power. This process is regulated by a specialized pocket watch created by the Sinner Shader, which serves as a replacement for his lost horns and controls the flow of Rosette's life force.