Motoki Yaze, a 16-year-old human esper, attends Saikai Academy as a classmate of Kojou Akatsuki. Descended from the Deva lineage, he belongs to the influential Yaze Clan, deeply involved in Itogami Island's Demon Sanctuary foundation through politics and business. This clan specializes in developing Hyper Adapters—psychic ability inheritors—though Motoki was initially deemed lackluster compared to his relatives. During childhood, he observed corrupt politicians and corporations engaged in illegal activities. Just before entering middle school, Kazuma Yaze briefed him on Kojou's condition, designating Motoki as Kojou's primary observer for the Lion King Organization. His Hyper Adapter abilities focus on manipulating sound waves and air currents. Using specialized headphones for concentration, his "Soundscape" power amplifies hearing for surveillance across kilometers, though loud explosions disrupt focus and risk auditory damage. Enhancer pills augment his powers: one pill enables "Air Propulsion" for midair movement, while multiple pills create a "Sound Clone" duplicate controlled via headphones. This clone demonstrated limited utility, destroyed immediately by Dimitrie Vatler after manifestation. Motoki typically maintains a relaxed demeanor but adopts seriousness during Itogami Island crises, often gathering intelligence to aid Kojou. He is Asagi Aiba's childhood friend, frequently encouraging her romantic pursuit of Kojou, though his observer role restricts direct conflict intervention. Following an internal Yaze Clan coup, he succeeded his father as family head and president of the Yaze Consortium, leveraging its financial influence to halt the Japanese government's order to destroy Itogami Island. He concurrently serves as director of the Gigafloat Management Corporation, overseeing the island's operations. Significant physical setbacks mark his involvement. During the Tartarus Lapse incident, magical damage and blood loss caused a temporary coma. Later, overusing his abilities and booster pills in another conflict resulted in internal organ damage and leg injuries, requiring extended hospitalization at a pharmaceutical research facility. This recovery hindered his observation duties and severed communication with Lion King Agency operative Koyomi Shizuka, whom he references as his girlfriend. In subsequent events, Nagisa Akatsuki treated his battle wounds, leading to a comedic misunderstanding about her intentions. Throughout these events, Motoki's loyalty to Kojou and Asagi remains consistent, exemplified by his parting words to Kojou during a critical moment: "Don’t make my childhood friend cry." He balances organizational obligations with personal friendships, often operating behind the scenes to stabilize situations through intelligence or political influence.