Soujiro Natsuki was once a troubled exam student, whose ill health prevented him from studying. Forced to spend some time at the Hinata Inn by his parents, Soujiro met Yoko Urashima, who was in charge of looking after the guests in the establishment's annex.
After staying at the inn, Soujiro recovered and passed his exams. Eventually gaining a job to work for the government, Soujiro became self-interested and took for granted those around him. After attempting to start up his own business, it failed after two years and, in an attempt to save her from being associated with the debt, he divorced his wife.
Years later, Soujiro returned to the Hinata House in an attempt to reclaim his lost memories of the place and met Yoko's ghost in the now-abandoned annex.
- Soujiro only appears in the novel Love Hina: Mystery Guests at Hinata Hotel.