Miyashita was an employee working for the Detnerat Company. He was killed by his employer, Rikiya Yotsubashi, the supreme commander of the Meta Liberation Army. He was very straightforward and honest with his boss, often joking with him and once making fun of his big forehead in a commercial for the company. His boss, Rikiya Yotsubashi, laughed off these comments, apparently having become accustomed to Miyashita simply speaking his mind around him. According to him, his mother died a year ago and he has no other relatives.