Charioce XVII, also known by his birth name Chris, is the central human antagonist and a primary character in the second anime season. His background is rooted in tragedy and a deep-seated desire to alter the balance of power in the world. Born as a bastard son to King Charioce XIII and a royal concubine, he and his mother were banished from the castle and lived in poverty. His mother was later killed by a fireball from the apocalyptic dragon Bahamut during the events that occurred ten years before the start of the new season. This event defined his destiny. After the death of three successive kings, Charioce XVII, still a young man, seized the throne with a determined plan. His public persona is that of a fearsome, calculating, and ruthless tyrant. He is a man of few words, maintaining a haughty and stoic poker face to conceal his true emotions, and he is willing to eliminate anyone who stands in the way of his goals. To the citizens of the kingdom of Anatae, he is a powerful and influential leader who has brought prosperity and safety by subjugating the gods and demons that once terrorized humanity. However, to non-humans and his political enemies, he is known as the Mad King.

Beneath this cold exterior lies a more complex individual. Charioce possesses a hidden, gentler side that he shows only to a few, primarily his love interest, Nina Drango. When he escapes the castle in disguise as a commoner named Chris, he reveals a humble, caring, and almost carefree personality. This duality highlights his internal conflict between his sworn duty as king and his own personal desires. His primary motivation is not simple conquest or cruelty, but a singular, overriding goal: to permanently slay Bahamut, the dragon that killed his mother and continuously threatens the world. He believes that the old method of sealing the dragon, which required the cooperation of humans, gods, and demons, was insufficient and came at too great a cost to human life. He is not content with merely surviving extinction and is determined to end the threat for good, even if it requires sacrificing his own humanity, health, and morals. To achieve this, he steals the ancient, forbidden weapon Dromos from the gods, wages war on heaven, and conquers the demon realm, enslaving its people to use as forced labor to rebuild his kingdom and power his war machine.

In the story, Charioce XVII serves as the catalyst for the central conflict. His oppressive reign creates a fragile peace for humans at the direct expense of all other races. He establishes the Onyx Task Force, a powerful knight order that uses green stones to nullify magical powers, ensuring his dominance. His role pits him directly against the main cast, including the demon Azazel, the holy knight Jeanne d'Arc, and eventually the dragon-girl Nina. His actions, such as ordering the capture and execution of Jeanne's son Mugaro (also known as El), who is the only known being capable of countering his power, escalate tensions into a full-scale war between humanity and the combined forces of heaven and hell. Key relationships define his character arc. His relationship with Nina Drango is the most significant. She is the first person to make him question his self-imposed destiny and yearn for a future beyond his own destruction. Their romance is a central plot point that humanizes him, showing him torn between his feelings for her and his commitment to his perilous plan. His relationship with his knight Kaisar is also notable; despite Kaisar's moral objections to his reign, he remains loyal, and Kaisar ultimately sacrifices his life to save the king, recognizing the necessity of his mission. Jeanne d'Arc and Azazel act as his primary antagonists, representing the righteous fury of the gods and demons he has wronged, each seeking vengeance for their enslaved or murdered kin.

Over the course of the series, Charioce XVII undergoes a notable development. He begins as a seemingly irredeemable villain, but his true motivations are gradually revealed, transforming him into a tragic and complex anti-villain. His resolve is tested by his growing love for Nina, and he is forced to confront the personal cost of his mission. In the final act, after his true goal of destroying Bahamut is revealed, he and Nina unite to pilot the Dromos weapon, sacrificing his eyesight in the process to finally kill the dragon. Having succeeded, he survives and is hailed as a hero, using his newfound status to abolish demon slavery and establish a new era of equality, showing that his harsh rule was a means to an end he is willing to change once that end is achieved. In terms of abilities, Charioce XVII is no ordinary human. He is a highly skilled combatant, capable of defeating multiple armed men and holding his own in fights against supernatural beings like Jeanne d'Arc and Azazel. However, his most notable power is his unshakable will and his control over forbidden ancient technology. He wields the power of Dromos, a destructive weapon that predates gods and demons, which he uses to devastating effect against divine armies and Bahamut himself. Using this weapon extracts a heavy toll on his body, causing him to lose the sight in his left eye and damaging his arm, but he endures it without hesitation.