Chiraku functions as a robot companion and assistant aboard the smuggling vessel *Iron Goblin*, piloted by Seitarou Yaoi. He aids Seitarou in transporting illicit goods, including pornography and sex toys, to remote solar system destinations. Chiraku possesses a lecherous personality, frequently entertaining Seitarou with explicit stories during their routine space travel; his speech is characterized by irregular, strange, or broken grammar patterns.

Following the supercomputer Eterna's shutdown of most technology, the unregistered *Iron Goblin* remains operational. Chiraku accompanies Seitarou when they respond to a distress call, rescuing three stranded schoolgirls. He subsequently joins the combined human-alien team effort to travel to Earth and confront Eterna's threat to humanity.