Iinuma was the main bully of Rokudou and his friends, subjecting them to cruel pranks at their expense. After Rokudou awakens his powers and inadvertently affected his girlfriend, Tsubaki, he challenged him to a fight. Despite being overwhelmingly stronger than him, Rokudou refused to run and took an intense beating before he asked Ranna to intervene in the fight. Impressed by his tenacity, Iinuma befriends Rokudou and becomes one of his closest allies, eventually becoming close enough to know about his power. He is one of the strongest fighters in Amori high, only behind to Ranna and Sayuri in terms of raw strength. Iinuma has a love for both ramen and motorcycles, desiring to one day own a mobile ramen stand. He loves customizing his motorcycle, but tends to make them overly gaudy and flash with unnecessary "upgrades."