Reiji Abidani

Reiji Abidani is the primary antagonist of Gamble Fish. He is a former mathematics student and currently works as the Dormitory Dean of Shishidō Academy. Abidani is highly intelligent and seeks to defeat Tomu Shirasagi in a gamble and/or have him killed.

History
Reiji Abidani was once a student of Princeton University in the year 1977. Though students were required to live in dorms, Reiji felt uncomfortable and the Dawn Family used their connections to allow a separate house to be built for him.

His field of study was mathematics, particularly prime numbers. He began working on proving the Reimann Hypothesis with his 'Abidani Formula' which, when completed, would've changed the way humans viewed the universe. However, he was conflicted by his work, wondering if he could really be the one to change the world, trying to figure out what God truly wanted for him.

The scheduled day of his presentation, Reiji put a gun to his head and loaded five of six bullet slots. Though everyone pleaded with him not to kill himself, telling him he could change the history of mankind, Reiji pulled the trigger. Though the gun did not fire, Reiji raced off to determine God's true answer, feeling that he only survived the firearm due to chance.

He eventually came across an underground gambling arena where a 'prisoner' would be strapped to an electrical chair and played against an opponent, known as the 'executioner' in a card game. If the 'executioner' won, the prisoner would be killed by 2000 volts of electricity but if the prisoner won, he could collect a substantial prize. Knowing that if he lost, his formula was worthless, Reiji decided to play.

His opponent wound up being none other than Isamu Shishidō. Isamu knew of Reiji and his work but never imagined that he'd see him in such a place. In the first round of their game, Reiji managed to win but lost in the second round and was given the sentence of death. However, just as the volts were to course though his body, the city of New York lost its electricity and Reiji survived, though his face was horribly disfigured.

With that, Reiji left the university and began travelling alone, breaking all contact and was not heard from again.

Plot
Abidani first showed up as the student dean after Tomu had defeated the dorm leader Kaizuka in a gamble. He then systematically explained how Tomu had won. From that point on Abidani continues to watch Tomu since he just "interests him".

He later sends Yuka to challenge Tomu in a blackjack gamble, and he was also more than happy to use a chainsaw to sever Tomu's finger after he bet it in a round.

After a long absence, Abidani appears again at the near conclusion of Tomu's billiard match against Rio just to see the looks of disappointment on her and Mika's faces since he had observed how Tomu managed to cheat right under everyone else's noses.

Later, Abidani sends his Abidani Seminar team to face off against Tomu's team in the dice battle.