Frederick Arthur is an antagonist in the story, serving as a primary rival to the protagonist, Ash Lynx. He is a vindictive and cruel former member of Ash’s street gang who later allies himself with the powerful mafia don Dino Golzine in an attempt to usurp Ash and gain power for himself. Arthur is a young American man, approximately twenty to twenty-one years old, with a tall stature. He has blond hair that is typically swept back from his face to show his forehead and ears, paired with thin eyebrows and narrow blue eyes. His common attire consists of a black shirt under a long-sleeved green jacket with a raised collar, beige trousers with a pocket on the right thigh, and black boots with beige soles that fasten with straps.

Personality-wise, Arthur demonstrates a particularly cruel streak and is described as spiteful, sly, and cunning. A dominant aspect of his character is his deference to whatever Golzine asks of him, as he is willing to betray anyone to achieve his goals. His primary motivation is a deep-seated vendetta against Ash Lynx, stemming from a knife fight they had in the past. In that encounter, Ash cut Arthur’s trigger finger, an injury that left him unable to properly hold or use a gun. This permanent disability fuels his desperate desire for revenge and to reclaim the status and power he feels he has lost. According to the character Shorter Wong, Arthur once debased himself by begging to be taken in by Golzine, going as far as to lick his feet, illustrating the lengths he will go to for an advantage.

In the story, Arthur serves as a persistent and treacherous threat to Ash and his allies. Recognizing Ash’s emotional attachment to the Japanese photographer’s assistant Eiji Okumura, Arthur perceives Eiji as a vulnerability. He kidnaps Eiji, whom he mockingly refers to as Samurai Boy, and uses him to lure Ash into traps. He forms a key alliance with Marvin, a subordinate of Golzine, to capture Ash. One of Arthur’s most significant and devastating actions is his orchestration of a scenario involving the mind-controlling drug Banana Fish. He forces two of Ash’s companions under the drug’s influence to fight in a deadly duel, ultimately compelling Ash to kill his own friend, Shorter Wong. This act solidifies Arthur as the central target for Ash’s subsequent revenge.

Arthur’s development throughout the narrative is defined by his escalating schemes and his ultimate failure. Due to his injured fingers, he is forced to abandon gunplay and instead relies on knives for combat, becoming proficient enough to fight Ash to a near standstill in a knife duel. In his final confrontation, Arthur attempts to gain the upper hand through a last-minute underhanded tactic, but this ultimately leads to his demise at Ash’s hands, settling the score between them. His notable abilities include his resourcefulness and cunning as a gang leader, his proficiency with a knife, and a stubborn, unyielding drive for vengeance that dictates his every action.