Mamoru Yamazaki is a supporting character in the anime series Big Order. He is a teenage male with brown eyes and black hair. His most notable ability is the power to manipulate sound waves, which he primarily uses for self-defense and to protect others. In terms of personality, Mamoru is initially portrayed as a shy and timid introvert who prefers solitude and tends to avoid conflict. However, when the safety of those he cares about is threatened, he demonstrates considerable bravery and determination, becoming more assertive and willing to fight. His motivations are strongly tied to loyalty and a sense of duty, particularly toward his adoptive sister, Eiji Hoshimiya, who is the main protagonist and the leader of a powerful organization known as the Order. This organization is dedicated to maintaining peace and order in a world where individuals possess unique and often dangerous abilities called Orders. Mamoru is a member of this organization and his role within the story involves supporting Eiji and the group's mission. His development throughout the series is marked by a transition from a passive and reserved individual to someone who steps up as a more active and integral part of the narrative. He struggles with self-doubt but is driven by a steadfast commitment to his sister and their shared cause, which makes him a courageous figure. His relationship with Eiji is central to his character, and his loyalty to her is a primary motivator for his actions.