Arai

is a prisoner in Hōzuki Castle.

Personality
Arai is shown to be a very laid-back individual. Friendly to new prisoners in Hōzuki Castle, he gladly shows them around and explains its inner workings. However, in reality, Arai is a scheming man who uses his kind demeanour to fool others around him.

Appearance
Arai is a tall and lanky man of fair complexion. He has olive-green eyes and red bushy hair. Like the other prisoners of Hōzuki Castle, he wears an orange prison jumpsuit with brown sandals.

Mujina Bandits Arc
When Boruto Uzumaki and Mitsuki were sent to Hōzuki Castle as its newest prisoners (secretly as a part of an official mission), the two boys were made cellmates with Arai and his other cellmates, Kedama and Kamata. He explained the layout of the prison to Boruto and Mitsuki. Later, they asked about the rumours of Tsukiyo, the second-in-command of the Mujina Bandits was really here as well. Arai explained that he was in solitary confinement after assaulting the prisoner Kokuri. As Arai off-handled noted that Kokuri was lucky to be administered to the well-accommodated hospital wing for such simple injuries, Boruto asked how to get in himself.

Arai said the only safe way to get in without the doctors seeing through the ruse is to eat a poison white berry of one of the Chinese lantern plants that surround the prison. Later, Arai was amazed at Boruto's luck in getting one of them, who without hesitation ate it. Arai played along with Boruto's ruse as he quickly fell ill and was taken to the hospital wing.

Later, Boruto asked Arai if he had any dirt on the chief officer of the prison Benga, saying he wanted to get back at the man. Arai had no idea personally but knew of a man who did. He took them to the prison's inner-boss Doragu. The shady man said he would only give such information if Boruto managed to get him the light bulb from the watchtower that regularly shined in his cell. While Boruto succeeded in acquiring the light bulb, he was quickly spotted by the guards. To Arai and everyone's shock, Boruto managed to escape with a blinding light, earning the info from Doragu. Later, it was learned one of the prison's all-access passes went missing three days ago, meaning a prisoner could have taken it.

As the prison was in lock-down, Boruto and Mitsuki concluded that since the pass was stolen on the same day Kokori was attacked in the hospital wing, it must be connected. They also concluded that it must be one of the cell-mates as at the time, their cell was the only one that the guard was in that day. Determined to find the thief before the guards inspected them, they found the pass on Kedama's belongings. Kedama insisted that it wasn't his doing, but Arai noted that Kedama had a history of working with the guards. As Kokuri was willing to hear Kedama's side of the story, Arai revealed that Kokuri was a member of the Mujina Bandits, making himself untrustworthy. Mitsuki, however, pointed out that no one in the cell should know that truth about Kokuri as he worked hard to keep it a secret. Revealing to know such a truth, Arai slipped up and revealed himself to be the culprit. He was then turned over to the guards.