Atori is a Dragon Knight from the dystopian alternate dimension known as La'cryma, serving as a significant antagonist in the narrative. His name in Japanese translates to finch. He has a tall and slender build, characterized by long, neck-length blonde hair that typically covers one of his purple eyes, and his lips are depicted as being dark in color.

His personality is marked by a volatile and unstable nature, often appearing mentally ill and exhibiting sadistic tendencies. He is prone to using extreme methods to achieve his goals and derives pleasure from belittling his rival, Karasu. This erratic behavior sets him apart from the other Dragon Knights, as he frequently clashes with them as much as with their enemies.

Atori's motivations and actions are deeply rooted in a traumatic past from his life in La'cryma. He had a younger sister named Sara, who died after accidentally stepping on a landmine. This profound loss is the source of his psychological instability and fuels much of his later behavior. In his role as a Dragon Knight, he is a formidable opponent, specializing in lightning-based attacks as his primary method of combat.

His journey involves a significant transformation. At one point, he loses his memories, reverting to a more innocent state. During this vulnerable period, he forms a powerful bond with a girl named Miho, whom he comes to believe is the reincarnation or a version of his deceased sister, Sara. This relationship is a catalyst for his development, moving him away from pure antagonism. Ultimately, he redeems himself through sacrifice, giving his life to protect Haruka during the second assault on Shangri'la. His complex arc and memorable nature have led to him being recognized as an ensemble darkhorse, becoming a favorite character for many viewers.