Kyouji Ogami

Dr. Ogami Kyoji is a World-renowned scientist and perfectionist, his hard boiled, no-nonsense personality makes for explosive spurts of cutting comments and poor Nanako is the unwitting recepient of such outbursts.
Dr Kyoji's apparent cold exterior and lack of emotions probably came about after experiencing tragic loss in his youth and as a result, he has worked tirelessly to to point of obsession to make sure the current incarnation of Nanako will live beyond her 20th birthday.