- Death the Kid (デス･ザ･キッドDesu za Kiddo?)
- Voiced by: Takako Honda (drama CD), Mamoru Miyano (Japanese), Todd Haberkorn (English)
- The son of Lord Death and the meister of the Thompson sisters. He suffers from a severe obsessive-compulsive disorder for symmetry: he views anything perfectly balanced on the right and left to be beautiful, and breaks down upon seeing anything off even by the slightest measurement (sometimes to the point of vomiting up blood and collapsing), which proves to be a major hindrance in his daily life and during battle. He chose to wield the Thompson sisters as twin guns to preserve his personal symmetry, and refuses to fight using one while the other is missing. Despite his constant belittling of the sisters, he does truly care for them. Kid is able to fight without his weapons through the use of a custom martial arts style. He can also summon a flying skateboard called Beelzebub as both transportation and a weapon. His status as a Death God grants him formidable power, particularly the destructive Soul Resonance "Death Cannon." While he is not required to collect souls or attend DWMA because of this, he does so anyway to fulfill his personal desires. His most distinguishing feature is the set of three white streaks on the left side of his head called the "Lines of Sanzu" which increase his godlike powers whenever they connect, though it depresses him whenever someone mentions them as they are not symmetrical. In the manga, it is implied that Kid's Lines of Sanzu are connected with the power or life-force of his father, Lord Death. As Kid grows stronger, his father grows weaker.