Rem Galleu is a petite Pantherian girl with long, flowing black hair that extends down to her waist. Her furred ears and sleek tail share the same striking black color, a rare trait even among her race. Her almond-shaped green eyes have a feline sharpness, and her calm, expressionless gaze, paired with her neat spruce eyebrows, gives her a doll-like appearance that reflects both quiet beauty and strong determination.

She possesses a slender and athletic physique, with visible muscle tone in her arms, legs, and sides. Her body shows no signs of excess, highlighting her training and discipline as an adventurer and summoner.

Rem’s attire is both practical and stylish. She wears a chest-length vest with attached shoulder pads, draped from a short jacket. A wide leather belt, adorned with numerous utility pockets, is wrapped around her waist. Her lower outfit consists of a layered cloth skirt, under which she wears tight-fitting shorts (spats) for mobility in battle.

Rem Galleu is generally composed, polite, and focused, often presenting herself with a calm and serious attitude. However, beneath her mature exterior lies a more emotionally vulnerable and easily flustered side particularly when it comes to affection or intimate situations.

She is deeply self-conscious about her small chest, which is especially uncommon among Pantherians. This insecurity frequently surfaces in comedic moments, particularly in contrast to Shera’s more open and voluptuous personality. Rem views her physique as a disadvantage in gaining Diablo’s romantic attention and becomes visibly embarrassed when Shera teases her or touches her body in playful ways. Her embarrassment intensifies in romantic or awkward scenarios, such as when she is asked to share a bed with Alicia while adjusting to living with Krebskulm.

Despite having devoted her life to destroying the soul of Krebskulm, which is sealed within her, Rem undergoes a dramatic emotional shift when the Demon King is eventually “born” into the form of a childlike girl. Although confused and conflicted, Rem is among the first to protect Krebskulm, revealing her compassionate and empathetic nature.

Rem struggles with public displays of affection and becomes easily flustered when others express romantic interest toward Diablo in front of her. She often becomes jealous or irritated when Shera engages in flirtatious or suggestive behavior around Diablo not only due to her own feelings for him, but also from a sense of being left out. As the story progresses, however, she becomes more proactive, often mimicking Shera’s actions to maintain her presence and assert her feelings.

While generally courteous to strangers and acquaintances, Rem reveals a snarky, pouty, and more emotionally open side to those she grows close to. Her internal struggles, paired with her subtle but growing affection for Diablo, contribute to her depth as a character and highlight the gradual transformation in how she approaches intimacy, friendship, and trust.

Rem Galleu was born into the Gad family of Caliture City, inheriting a dark and dangerous legacy as the vessel of the Demon Lord Krebskulm’s soul, passed down from her mother. Aware that her death would trigger the resurrection of the Demon Lord, Rem lived under the constant shadow of this burden from an early age.

At some point, Rem left her family and chose the path of a Summoner, seeking strength and knowledge that would allow her to confront the fate sealed within her. During her journey, she met Celestine Baudelaire, a high-ranking official of the Mage’s Association. Celestine attempted to bring Rem into the Magician’s Society, both to protect her and to prevent Krebskulm’s potential revival. However, Rem declined the offer, choosing instead to become an adventurer and take responsibility for her destiny by finding her own way to eliminate the Demon Lord’s soul.

After contracting with several Summoned Beasts, Rem devised a bold strategy: to fight a Demon Lord, she would summon one. Her plan led her to Starfall Tower, a place sacred to Summoners. There, she encountered Shera L. Greenwood, an Elf who also sought to summon a Demon Lord for her own reasons. Unbeknownst to each other, the two performed the Summoning Ritual simultaneously, resulting in the unexpected appearance of Diablo, a powerful entity from another world. However, due to a magical reflection caused by Diablo’s equipment, both girls became magically bound to him instead of the other way around.

Thus began Rem’s journey alongside Diablo, not only to find a way to eliminate Krebskulm’s soul, but also to navigate her growing bonds with her companions.

Volume 1
In an effort to gain the strength necessary to confront the Demon Lord Krebskulm sealed within her, Rem Galleu, alongside Shera L. Greenwood, performs a summoning ritual at Starfall Tower to call forth a powerful being from another world. Both girls intend to summon a Demon Lord and bind him to their will through an Enslavement Ritual.

However, the ritual does not go as planned. The being they summon is Diablo, an overwhelmingly powerful man who arrives in the form of his Cross Reverie game avatar. Due to the magical effect of The Demon King’s Ring that Diablo wears, the Enslavement Ritual is reversed. As a result, Rem and Shera become magically bound to him instead, marking the beginning of an unexpected journey. While Rem initially objects to this outcome, she chooses to stay with Diablo, believing that he may be the key to finally defeating the Demon Lord sealed inside her.

Shera L. Greenwood
Shera is an Elf whom Rem meets at Starfall Tower, where the two independently perform a summoning ritual to call forth a Demon Lord. Their simultaneous efforts result in the summoning of Diablo. Since then, the two frequently argue over who actually summoned him, often in a lighthearted and comedic fashion. Despite their bickering, Rem and Shera develop a close friendship and support each other throughout their journey.

Diablo
Diablo is the entity Rem and Shera summon from another world. Rem initially seeks to summon a Demon Lord in hopes of using his strength to defeat Krebskulm, the Demon Lord whose soul is sealed within her. Although the summoning ritual unexpectedly results in her becoming magically bound to Diablo, Rem gradually comes to trust and care for him. Over time, their relationship deepens, eventually culminating in marriage in Volume 9.