Lag Seeing is the main protagonist of the story, a young Letter Bee with a focused and determined mindset. He was born on the Day of Flicker, the day the artificial sun of AmberGround first went dark. When he was a child, his mother, Anne Seeing, was kidnapped and taken to the capital, Akatsuki. He himself was sent as a delivery to his aunt by the Letter Bee Gauche Suede, who became his idol and inspired him to become a Letter Bee. Physically, Lag is a short boy with ghost-white hair and a single purple eye; his left eye was removed by his mother and replaced with red Spirit Amber, which enhances his abilities. His personality is marked by a strong sense of purpose and emotional sensitivity. He cries easily, but this reflects his deep empathy and caring nature. He is gentle, protective, and possesses an unwavering commitment to delivering letters, viewing the task as a way to convey the feelings of the sender. He is also searching for his lost mother. In his role as a Letter Bee, Lag travels across AmberGround with his Dingo, Niche, a girl he rescued from a Gaichuu who chose to stay by his side. He also forms bonds with Sylvette Suede, Gauche's sister, and the other Bees at the Bee Hive. His relationship with Gauche becomes a central part of his journey: after Gauche disappears and later appears as a member of the resistance group Reverse with no memory of his past, Lag repeatedly tries to restore Gauche's heart and memories. Lag's most notable ability is his skill with the Shin Ganjuu, the heart bullet gun. He loads fragments of heart into the gun and fires them at targets, and he can control the direction of the shot. His left eye, made of Spirit Amber, allows him to perceive the emotions and memories contained within letters and objects, making him uniquely suited to his work. Over the course of the story, he matures through his encounters with Gaichuu, his quest to find his mother, and his efforts to save Gauche, learning about sacrifice, the weight of emotions, and the power of human connection.