Arashi was protective of Hana, going as far as even murder to save her. Once, Hana was nearly raped by a group of boys whose illegal activities were reported to the police by her. In a fit of rage, Arashi beat them up, nearly causing the death of some of them.
Arashi's first appearance was in the initial chapter of the series, "Slow Awakening". He protected Natsu from drowning and being bullied by Semimaru and later on travelled towards Bungo Fuji and then Kumamoto Castle, there realizing that Botan's story probably was the truth.
He then hiked towards Tokyo with Natsu and Semimaru. Arrived at the destroyed town, Arashi fell into despair because he thought Hana to be dead and contemplated suicide by drowning, but got saved by Aramaki's dogs.
Semimaru and Natsu managed to give him back his courage, and Arashi decided to return to Bungo Fuji together with the others. After rescuing the rest of their team members, they continued sailing around Japan but ran aground at a beach where they came across Ango and Ryou who helped them getting the ship off the rocks.
In the Fuji, Arashi gave it his best to stop the countdown in order to protect the country, Hana and all the other people scattered across Japan from being annihilated.