Adette Kistler is a prominent character known for her striking long blonde hair and bold, form-fitting leather attire, which gives her a distinctive and intimidating appearance. Initially serving as a member of the Siberian Railway Guard, she is introduced as a competent and ruthless agent who is tasked with pursuing the escaped convict Gain Bijou. Her early role in the story is defined by her dedication to her job, which leads her to arrest the protagonist, Gainer Sanga, on suspicion of being involved with the Exodus movement.

Adette's personality is characterized by a fearless and highly proactive nature. She does not hesitate to undertake reckless actions to achieve her objectives, including infiltrating the civilian exodus convoy with the mission to assassinate Princess Ana Medaiyu. Her motivations are rooted in a strong sense of self-preservation and a desire for powerful, capable individuals. She professes an attraction to strong men, and her loyalties and affections often shift towards whoever she perceives as the most formidable or dominant figure at the time. This capriciousness is a core part of her character, as she pursues her own interests with a single-minded devotion that often disregards conventional logic or authority.

Throughout the story, Adette's relationships are central to her development. She begins as the lover of Yassaba Jin, the commander of the Siberian Railway forces. However, after being stranded with the Exodus group, her allegiance begins to change. She develops a complex dynamic with Gainer, at times acting as a mentor or older sister figure, while also showing a clear romantic interest in him as a strong prospect. Her most significant relationship forms later with Gauli, a fellow combatant. After Gauli is turned into an enemy by the Over Devil's Over Freeze ability, Adette is the one who brings him back to his senses with a passionate kiss, demonstrating a more emotional and ninja-like side to her character.

Adette undergoes a notable evolution in her role and status. After failing to stop the Exodus, she becomes disillusioned and turns to alcohol. Her path changes when she accepts a position as a teacher at the Siberian Railway, where she is assigned to Gainer's class. Despite her new profession, her unorthodox and selfish behavior persists; she is known for eating the students' supplied bread and leading them on nighttime raids to steal food from transport trains. Her resourcefulness and leadership qualities shine through when she organizes the Adette Corps, a group of refugees armed with stolen silhouette engines, revealing a natural talent for command that earns her the loyalty of followers like Kejinan and Enge, who call her big sis.

In terms of abilities, Adette is a highly competent combat agent. Her thorough understanding of the Siberian Railway's internal workings makes her a valuable asset in battle, and she is skilled at piloting Overman mecha. She later pilots her own custom machine, which is notably painted red. Her personal weaknesses are few, but she has a well-documented and intense fear of slugs.