Hitoshi Sora
Hitoshi Sora is a cultural anthropologist and space alien. His research brought him to visit Earth, and he is currently in disguise as the biology teacher at Hazumu's high school. His unfamiliarity with human ways provides the series with an outside perspective on love - the focus of Sora's research. Additionally, his views on other subjects, such as friendly competition or war, provide a somewhat existentialist point of view. The alien's research, explained in the manga, is of great importance to the survival of his species as he fears that if his currently rather unemotional people do not rediscover passions like love, they may all eventually die out.