Kitazawa was Eiri Uesugi's tutor when Eiri lived in America with Tohma Seguchi. The manga depicted a warm and friendly relationship between them, which often seemed more like friendship despite Eiri addressing Kitazawa as "sensei." However, unbeknownst to Eiri, Kitazawa harbored pedophilic desires towards his young student.
In both the manga and anime, Kitazawa drops a bottle while trapping Eiri inside a dark apartment one night. Two men enter the scene, and Kitazawa allows them to go 'first' for a fee of $10.
During the assault, Eiri manages to grab a gun and shoots Kitazawa, killing him. Tohma Seguchi finds Eiri at the apartment and comforts him afterward. Feeling responsible for what happened to Eiri, Tohma believes he should have vetted Kitazawa more thoroughly and could have prevented the tragedy.
Kitazawa has a younger brother named Yoshiki, who is an MTF transsexual. In Gravitation 2, it is revealed that Kitazawa also has a young son named Riku.
