Kimihiko Nikaido

Kimihiko Nikaido (二階堂 公彦, Nikaidō Kimihiko) is the father of Maki Nikaido and a researcher at the Infectious Disease Center of Asia.

Character
Nikaido is presumed to be a widower, left to raise his daughter Maki alone. He home schools Maki, giving her complicated homework assignments which are later revealed to be part of his research into the virus. Nikaido regularly gives his daughter injections for her low blood sugar, and has her routinely take her temperature.

Plot
He first appears in the Infectious Disease Center of Asia. Under orders from Washington, they were to analyze a virus sample taken from Bangnum, Thailand.

After a discussion concerning the effects of the virus, Professor Kujo suggests that the virus is a weapon, saying "Many countries are secretly undertaking the development of virus weapons. Some countries succeed." Professor Nikaido then informs Professor Kujo that the virus weapon has failed, saying, "A virus weapon is a success only if it comes with an antidote. Otherwise, the user will also be infected. I'm sure there was an antidote, but it's of no use now." When asked why, he replies, "This virus has mutated within the last 20 hours."

Nikaido later gives his daughter what is assumed to be the antidote for her to give to Kujo.

Professor Nikaido eventually calls Kujo and tells her to come to the lab. Kujo arranges for Daisuke Matoba, who is a leader of a bio-terrorist group, and his group to come with her. At the lab, Kujo reveals her involvement with the virus, and Matoba explains to Professor Nikaido that what they are doing will benefit the earth's ecosystem, claiming that, "If there are too many, all we are doing is decreasing that number." K finds out that Professor Nikaido has indeed created an antidote already. K and company beg for said antidote, but Professor Nikaido does not give it to them. He decides to incinerate the antidote and delete the data for the antidote. He finally commits suicide by injecting himself with the virus, much to Kujo's dismay, as she tries to convince him that people like himself will be needed in the New World. Kujo shortens Nikaido's suffering by shocking him to death so that he wouldn't have to die from the painful effects of the virus.

Later on, it is discovered that Maki's homework had a hidden message in it left from her father concerning an antidote for the virus, which ultimately helps Koichi Matsudo to successfully create an antidote.