Jihriel is an angel from the celestial realm known as Heaven, introduced in the second season of the anime. He is formally one of the apostles serving the 64 gods of Heaven, acting as a messenger of God. His appearance is that of an adult male with long, blonde hair that reaches past his hips and distinctive turquoise eyes. While he possesses this elegant and somewhat androgynous humanoid form, Jihriel also has the ability to transform into a much smaller, bird-like creature resembling a cute yellow chick, which is the form he often takes after forming a pact with the protagonist, Lloyd.

Jihriel possesses a complex and often contradictory personality. On one hand, he is a proud and dignified angel who looks down on humans, frequently referring to them as fools and expecting subservience. He has an extremely high opinion of himself, believing his sacred magic, Lux, to be invincible and infinite. However, this arrogance masks a more frivolous and hedonistic nature. He is notorious for his weakness for attractive young women, which first draws his attention to the human world when he becomes entranced by the singing and performance of the sisters Isha and Saria. He is often seen blushing, drooling, or making embarrassing remarks when captivated by their beauty, a trait that frequently gets him into trouble and leads his demon companion, Grim, to call him a perverted angel. Beneath his conceited exterior, Jihriel is also surprisingly emotional and prone to outbursts when things do not go his way.

In the story, Jihriel's primary role is that of a source of sacred magic, a power Lloyd becomes determined to learn. He first appears as an antagonist when Lloyd, sensing his gaze from the heavens during a church concert, teleports directly into the angelic realm. Jihriel is shocked and angered by the intrusion of a human and a demon (Grim). He initially refuses Lloyd's request to teach him sacred magic, leading to a magical duel. During the fight, Jihriel showcases his signature ability, Lux, creating countless feather-like swords made of light that are as hard as steel. He boasts that this light dust is invincible, but Lloyd, through relentless experimentation and analysis, deduces that Lux is neither infinite nor invincible and that its use drains Jihriel's mana. After exhausting his power and nearly fading from existence, Lloyd generously shares his own overwhelming magical energy, fully restoring Jihriel.

Seeing this as a perfect opportunity to finally descend to the human world he so desires, Jihriel offers to form a contract with Lloyd to grant him divine magic. However, he secretly attempts to take over Lloyd's body entirely. This plan fails spectacularly as Lloyd's immense mana reserves prove far too great, and Jihriel finds himself trapped, forced to inhabit only Lloyd's left hand. On Lloyd's hand, he manifests as a small eye and mouth, becoming a familiar bound to the prince. Through this pact, Lloyd immediately gains an intuitive understanding of sacred magic's language. His first attempt to cast Lux results in a grotesque, colossal manifestation that Jihriel, now awestruck, interprets as a divine revelation. From that moment on, the proud angel adopts a much more respectful tone, calling Lloyd "Lloyd-sama".

His key relationships are centered on this new life on Earth. His bond with Lloyd is the most significant, evolving from one of an arrogant celestial being to a fascinated subordinate who is in constant awe of Lloyd's magical genius and innocent obsession with the mechanics of spellcasting. He frequently clashes with Grim, his fellow familiar. Their relationship is highly combative and competitive, with Grim often physically stopping Jihriel from his perverted antics or mocking his failures. He develops a particular attachment to Isha and Saria, the young singers whose performance first captivated him, but his infatuation extends to nearly any attractive female he encounters.

Jihriel’s development is a marked journey from a powerful, free-willed angel to a cheeky but loyal companion. He is humbled by his defeat at Lloyd's hands and his subsequent failed possession attempt. Although he retains his narcissistic and lustful tendencies, he becomes a less arrogant and more cooperative member of Lloyd's magical team. His powers, once wielded for his own pride, are now combined with Lloyd and Grim in combat. In battle, he participates in a "triple recitation," using the mouths that manifest on Lloyd's hand to perform incredibly powerful, combined magical attacks. He serves as a living grimoire for sacred magic, but he is also a source of comic relief, often being the victim of slapstick humor due to his own exaggerated personality.

His notable abilities center entirely on sacred magic. His signature spell, Lux, allows him to materialize light into weapons, predominantly swords, which he can use for both offense and defense. As an angel, he inherently possesses the power to bestow sacred magic upon others, which he agrees to do for Lloyd. In his reduced state as a familiar, his power is integrated with Lloyd's. He can channel his magic through him, and when Lloyd uses sacred magic like Lux, the results are amplified to terrifying, often uncontrollable, degrees. His mana is not limitless, and its depletion can cause him to fade away, as nearly happened during his first encounter with Lloyd.