Michio Sonezaki is a supporting character who appears in both the 2006 anime series Night Head Genesis and the 2021 reimagining Night Head 2041. His background is not extensively detailed, but he is consistently portrayed as a male adult with distinctive physical traits: in Night Head Genesis he has dark brown hair and blue eyes, while in Night Head 2041 he is depicted with short blue hair, black eyes, a facial scar, earrings, a piercing, and a hair streak.

Sonezaki’s personality is characterized by an intentionally abrasive and exploitative demeanor. He behaves in a deliberately unpleasant manner toward others, using and manipulating people for his own advantage, yet he remains surprisingly popular despite his attitude. His motivations appear to revolve around self-interest and a willingness to take advantage of those around him, though specific goals are not clearly defined.

In the narrative, Sonezaki fulfills a supporting role, often acting as an antagonist or obstacle to the main characters. His key relationships are not elaborated upon in available material, though his interactions with other characters are marked by his manipulative nature. There is no indication of notable superhuman abilities; his influence seems to stem from his personality and social maneuvering rather than any supernatural gifts. His development across the story is minimal, as he remains a consistently self-serving figure throughout his appearances.