In Japanese mythology, all noble families are descended from dragons, who know their mates on first sight. After meeting said mate, their sanity depends on their mate's presence and acceptance. Consider Himemiya Yukio, a noblewoman. Upon separation from Komari (who had accepted her many times over), she started refusing to eat, and thought she was hallucinating (again) when Komaridid show up. Diagnosis: Her Inner Dragon couldn't live without its mate.