|First Appearance||Chapter 133|
|Last Appearance||Chapter 186|
|Status||University Professor |
Chief of a variety of Research Insitutions
|Known Relatives||Setsuna Honjou|
Fumio is a messy and unkempt-looking man. He refuses to stay in crowded areas as he dislikes being with people of lesser intellect. Despite these qualities however, Fumio is a brilliant mathematician. He is able to build complex machines and was even consulted by athletes for the correct postures and angles they should make to achieve the best results. He is a cardboard fanatic and dedicated his life's research to it, going as far as hiring delinquents to help him turn the concrete jungle into a cardboard one. He himself lives in a four-story cardboard house surrounded by cardboard furniture, including a chandelier, dressers, and stairs. He also has the ability to talk for hours on end about the greatness of cardboard.
Personality-wise, Fumio is a rather eccentric person. He is generally nice and a little prone to panicking. Yako felt Fumio shared a few quirks that Harukawa possessed. Later in the series however Fumio is revealed to have a sinister side. He was corrupted by Sicks and was completely manipulated to the point where he was willing to give away the lives of his daughter and his own. Fumio was aware of this though and honestly did not want to be controlled by Sicks, but he was not able to hold on to his free will when he was under Sicks' presence.
Fumio is introduced shortly before DR's attack on the city. Yako comes across him as he was cooking a huge fish he had just caught and Yako, being hungry as always quickly goes over to get a taste. After DR's attack Yako meets Fumio again when she goes to the flood site. It is here when Fumio first displays his abilities at solving problems through calculations and the reveal of his relation with Setsuna Honjou.
Fumio later plays a vital role in Vijaya's attack. Upon the discovery of Tierra's identity as a New Bloodline member Fumio was listed as one of the people who had once dealt with Tierra. As Sasazuka, Yako and Godai were about to interview Fumio, Vijaya and Kasai attacked the hotel they were in. Fumio along with the other three were forced to flee from their attackers. After revealing he had kept some important documents relevant to Tierra's case in a forest in the rural area, Fumio, Sasazuka, Yako and Godai quickly escaped from the hotel and made their way to the forest. Their pursuers gave chase however and the police force dispatched to assist in the mission were all incinerated by Kasai. To make things worse, the forest gave Vijaya an incredible advantage due to his powers and Fumio had forgotten the exact location he had hid his documents. Godai and Sasazuka prevailed over Vijaya however and Fumio finally found the documents.
After the invasion of Green Corp., Yako and Neuro go for a fishing trip with Sasazuka, Ishigaki and Shizuka. Yako, being unable to catch anything, quickly called Fumio over to help her as the loser of the fishing game would have to obey the winner's command (in this case, Neuro was leading at that point). Fumio comes over and manages to catch Yako a couple of criminals instead of fish. During the fishing game Fumio talks to Yako about Setsuna and sheds some light on her death, saying that it wasn't just a simple disease like what Harukawa thought it was.
After the fishing trip, Sasazuka goes on a vendetta to kill Sicks but is killed himself. Yako meets up with Fumio after the funeral and after exchanging some jokes Yako bitterly asks why Fumio had betrayed them. Fumio grows solemn and gains a very dark expression at this point, revealing to Yako a "6" symbol scarred on his torso. He reveals he had been working for Sicks the entire time and the role he played in Vijaya's attacks and Setsuna and Sasazuka's demise. Fumio starts shouting and yelling like a madman at this point. He injects a serum into his neck and falls off the bridge, sorrowfully telling Yako he was sorry and telling her his home was in her hands.
Later, after Neuro and Yako break up Aya goes to Yako to consult her. After comforting Yako, Yako remembers Fumio's last words on his house. Realising he may have left a final clue there Yako and Aya immmediately go over. Sure enough, Fumio had left a letter for Yako containing vital information which could put Sicks in a disadvantageous position. In the letter, Fumio states he wrote it not as an apology to Yako but as thanks for being his friend. In the letter was Sick's hidden location.