Arthur Campbell serves as the second officer of the battleship Silvana, a key military vessel in the nation of Anatoray. He holds a position on the ship's command crew, placing him in a role of significant responsibility within the vessel's hierarchy. As an officer from Anatoray, his duties involve overseeing operations and ensuring the smooth functioning of the ship under the authority of his superiors.

In terms of personality, Campbell is characterized by a strong sense of loyalty that is tempered by his own moral compass and professional judgment. While he demonstrates unwavering devotion to his commanding officers, namely Captain Alexander Row and the ship's owner, Sophia Forrester, he is not a subordinate who follows orders without question. His defining moment of principle occurs when Captain Row orders the Silvana to open fire on a vessel belonging to Delphine Eraclea during a critical ceremony. Campbell refuses to comply with this direct command, doing so on the grounds that the attack would endanger the life of the Empress and other military commanders who were present below. This act of defiance highlights that his commitment to the lives of his leaders and innocent personnel outweighs his duty to obey a reckless order.

Campbell's primary role in the story is as a supporting officer aboard the Silvana, contributing to the functionality and decision-making of the ship's command structure. His key relationships are with his two direct superiors. He serves under both Alexander Row and Sophia Forrester, showing loyalty to each while maintaining the ability to exercise his own judgment when he believes an order is wrong. This dynamic illustrates that his respect for authority is based on reason and the protection of others, rather than blind allegiance. His development as a character is demonstrated through his willingness to disobey a command from a superior officer, an act that reveals his integrity and his prioritization of safety and duty to the crown over military aggression. No detailed information is available regarding his background before serving on the Silvana, his personal motivations beyond his sense of duty, his relationships with other crew members, or any notable abilities outside of his standard responsibilities as a ship's officer.