Garnet MacLaine is a major in the military of the Gillard New Emirates, a position that sees her frequently pursuing the secrets behind the Resonance process. She is a tall, dark-skinned woman with violet hair and striking odd-colored eyes, possessing one green eye and one red eye, a feature that hints at her true nature. She holds the rank of major and is known for her exceptional skill with a katana, a weapon she has carried ever since a visit to Japan.

In terms of personality, Garnet typically presents a high-handed and sadistic demeanor, appearing ruthless and letting nothing get in the way of her duties. Despite this harsh exterior, she displays a completely different side in the presence of Prince Asim Jamal, to whom she is fiercely loyal. Her devotion to the prince is absolute; she even orchestrated the death of Asim's older brother to help secure his position as the first heir to the throne. This relationship carries a maternal quality, as she has acted to protect and care for Asim since he was a child.

A major revelation in the story is that Garnet is not human but a Dragon. It is disclosed that she had formed a Resonant bond with Asim fifteen years prior to the main events of the narrative. Her role in the story is that of a formidable antagonist and loyal protector. She serves as a direct adversary to the protagonists, at one point severely wounding Akira Souya with her sword, an act that causes the dragon Makina to go berserk.

Garnet is eventually defeated in battle by the dragon Gio, and she is seemingly destroyed in an explosion alongside Prince Asim. However, her fate does not end there. She later resurfaces after being absorbed by the entity Thanatos, making a final appearance as part of the transformed final antagonist. Regarding her abilities, beyond her mastery of the katana and superhuman combat skills, her true form as a Dragon is a bipedal, wyvern-like creature possessing immense strength and durability.