Arai in Naruto

Mitsuki and Boruto Uzumaki were placed in the same cell as Arai and his fellow captives Kedama and Kamata after they were covertly transported to Hzuki Castle as its newest prisoners. He gave Mitsuki and Boruto a tour of the prison's layout. Later, they inquired about the claims that Tsukiyo, the Mujina Bandits' second-in-command, was indeed present as well. Arai claimed that he was held in isolation because he had abused Kokuri, another prisoner. As Arai offhandedly said that Kokuri was fortunate to have received treatment for such minor injuries at the well-equipped hospital wing, Boruto inquired as to how he might enter as well. Arai said that eating a poison white berry from one of the Chinese lantern plants that surround the jail is the only risk-free method to enter without the physicians spotting the ploy. Later, Arai was astounded by Boruto's good fortune in obtaining one of them and his consumption of it without hesitation. Arai went through with Boruto's ploy even though he got sick very soon and had to be transported to the hospital wing.

Later, Boruto expressed his desire to avenge Benga by asking Arai if he had any dirt on the prison's commanding commander. Arai didn't know, but he knew a man who did. He led them to Doragu, the prison's internal boss. The shady guy said that he would only provide this knowledge if Boruto could secure for him the watchtower lightbulb that frequently shone in his cell. Boruto was able to get the light bulb, but the guards noticed him right away. Arai and everyone else were shocked when Boruto used a blinding light to flee, getting the information from Doragu. It was then discovered that one of the prison's all-access permits disappeared three days prior, suggesting that a prisoner may have taken it.

Since Kokori was attacked in the medical wing on the same day the pass was taken, Boruto and Mitsuki reasoned that the two events must be related while the jail was under lock-down. Since their cell was the only one the guard was in that day at the time, they also came to the conclusion that it must be one of their cellmates. They discovered the pass on Kedama's possessions, determined to catch the thief before the guards looked them over. Arai pointed out that Kedama had a history of collaborating with the guards despite his insistence that it wasn't his fault. Arai disclosed that Kokuri was a member of the Mujina Bandits, rendering him unreliable, since Kokuri was prepared to hear Kedama's version of the tale. However, Mitsuki emphasised that because Kokuri fought so hard to keep it a secret, nobody in the cell should be aware of that information. Arai tripped up and admitted that he was the offender after revealing that he knew such a thing. The guards were then given control of him.

Arai is shown to be a very laid-back individual. He is extremely strategic and analytical but eventually slips up and makes a mistake by revealing himself as the culprit.

Arai is shown to have olive green eyes and red bushy hair. He wears a standard prisoner uniform, which consists of an orange prison jumpsuit and brown sandals.

There is no information available about Arai's abilities and strengths. However, he is shown to be knowledgeable about Hōzuki Castle and its inner workings. Although smart, he is also shown to be cunning and deceitful.