Garnet MacLaine is a major in the military of the Gillard New Emirates and serves as a secondary character. She is a tall woman with a dark tan and sharp, attractive features. Among her most distinguishing physical traits are her oddly colored eyes, with her right eye being green and her left eye red. Her hair is a shade of violet, and her physique is notably curvaceous. She wears a form-fitting, revealing version of the Gillard military uniform that emphasizes her figure. Garnet is almost never seen without a katana, a weapon she has carried ever since a visit to Japan, and she is extremely skilled in its use.

In terms of personality, Garnet presents herself as high-handed and often sadistic, carrying out her orders with a ruthless and pragmatic demeanor. She is intensely devoted to her duty and does not allow her personal feelings to interfere with her missions. However, this cold exterior dramatically shifts in the presence of Prince Asim Jamal. Before him, she becomes a fiercely loyal and dedicated follower, showing a maternal side that seeks to protect him. Her actions to secure his position are ruthless; she was complicit in the death of Asim's older brother to make him the first heir to the throne.

Garnet’s motivations are intrinsically linked to her bond with Prince Asim. Her primary drive is to protect him and advance his interests, a commitment that stems from their first meeting when Asim was a child. Her role in the story is that of an antagonist and a formidable agent of the Gillard military. She is often depicted pursuing the secrets behind the Resonance process and clashing with the main protagonists. In a pivotal turn, she is revealed to be a Dragon who had resonated with Asim fifteen years prior to the series' events. Her true dragon form resembles a bipedal wyvern.

Throughout the narrative, Garnet’s key relationships are defined by her loyalty to Asim. She acts as his confidant and protector, a role that feels both maternal and professional. Her actions against other characters are often in service to him or her mission. She notably cuts Akira Souya with her sword, an act that causes Makina to go berserk. In combat, she proves to be a powerful opponent, but she is eventually defeated by the dragon Gio. In the final stages of her story arc, Garnet and Asim are engulfed in an explosion created by Gio and are presumed dead. However, they later reappear, having merged with the entity Thanatos, and she appears as part of the final opposition in the series' concluding episode. This final transformation represents her ultimate development, as her physical form and consciousness are absorbed into a greater, world-threatening force while still acting in opposition to the main characters.