|Hair Color||Dyed Silver|
This section contains plot details about the novels.
Daiya has dyed silver hair and wears in three piercings in his right ear. At the end of Volume 7, his natural hair color is revealed to be black, similar to Kazuki's.
A self-centered and arrogant student who dyes his hair silver and wears three piercings in his right ear. He is also the class president and a shrewd friend of Kazuki.
Kamiuchi believed only he could see Kokone's real beauty during middle school, but Daiya ended up dating her before he could do anything.
Daiya used Kamiuchi and his box in order to learn how to master his own. He tricked Hoshino into believing that he was the real owner. In order to save Hoshino, O appears at the end of the fourth round of Kingdom Royale and helps Daiya kill the real Kamiuchi which terminates the box.
It is later revealed that he had actually obtained a box called the "Shadow of Sin and Punishment". He used the power of his to start the dog-human epidemic and bring people under his control. Daiya is later brought into the "Wish-Crushing Cinema" as an attempt to stop him. He forces Kazuki to come into the Cinema himself and has a standoff with him. After Kokone stabbed herself to get Daiya distracted, Kazuki destroyed his box.