Piper is a supporting character in the anime Marine Boy, serving as a crew member of the Ocean Patrol's P-1 patrol boat alongside Marine Boy and fellow sailor Bolton. He is the slimmer of the two crewmen, a trait that visually distinguishes him from the heavier-set Bolton, and, like other Ocean Patrol recruits, he wears the red beret that is part of the standard uniform. Aboard the P-1, Piper functions mainly as operational support: he accompanies Marine Boy on assignments, takes part in investigations of distress signals and abandoned vessels, and supplies the kind of practical knowledge the crew relies on during missions. Together with Bolton, he forms the hero's regular companions on the boat, and the pair contribute occasional comic relief to the adventure-driven episodes.

Personality-wise, Piper tends to become anxious when situations turn dangerous, and his panicked reactions are one of the show's recurring lighter moments. His crewmate Bolton, who pilots the submarine, is frequently shown steadying him, most notably through the catchphrase "Pipe down Piper," used whenever Piper lets his nerves get the better of him. His personal background and deeper motivations are not developed in detail; he is presented as a dutiful sailor whose main concern is carrying out patrol duties alongside his teammates. His key relationships are with Marine Boy, whom he assists on missions and who leads the P-1, and with Bolton, his fellow crewman and the one who usually calms him down under pressure. The series does not attribute any special powers or unique equipment to Piper; his value lies in his role as a sailor, his familiarity with patrol procedures, and his steady presence as part of the team that keeps the P-1 operational. He does not undergo a significant personal arc, instead appearing throughout the series as a dependable supporting figure who remains consistent in his duties and his place within the crew.