John, a German Shepherd originally serving as Hidetoshi's hunting dog, joins the wild Ohu Mountain pack after losing a leadership challenge to Riki. His personality exhibits arrogance, snobbishness, and a short temper, often manifesting as rudeness and distrust. He takes excessive pride in his European breed heritage and consistently overestimates his strength, leading to reckless challenges against powerful opponents like Riki and Gaia. His defeat by Riki proves pivotal, humbling him and fostering significant personal growth, deep loyalty to the Ohu Army, and a close bond with Gin.

John first encounters Gin as a puppy during a hunt, intercepting a bird the young dog was retrieving. Later, accompanying Hidetoshi, he attacks Gin and Daisuke after they kill a female bear, then kills her cubs without remorse, reflecting his ingrained belief that all bears are enemies. After joining Riki's forces, he is entrusted with conveying messages about the impending battle against Akakabuto. During recruitment across Japan, he defeats Henry III in Kyushu, securing vital allies. In the final assault on Akakabuto, he leads the fourth squadron alongside Benizakura and Wilson, executing diversionary tactics enabling Riki and Gin's decisive attack.

Following Akakabuto's defeat, John remains with the Ohu Army. He participates in the conflict against the wolf Gaia, falling into a ravine with Musashi. Though surviving, he struggles against Gaia's superior strength. Years later, during the Hogen arc, John serves as Gin's adjutant alongside Akame. Searching for Gin's missing mate Sakura, the group encounters Hougen's forces. John is captured and tortured alongside Gin and Hiro. During an escape attempt, he sustains a severe abdominal injury. Choosing to stay behind with allies Lefty, Tommy, and Ross to delay pursuers, he enables Hiro and Reika to flee. Despite his wounds, he defiantly confronts Hougen, enduring further torture without yielding. Unable to break his spirit, Hougen leaves him for dead.

Found by Weed, Sasuke, and Hook, John's final request is to speak with Akame. Hook impersonates Akame, falsely assuring John that reinforcements have arrived and Gin is safe. John passes away shortly afterward, his final thoughts envisioning pursuing Akakabuto in the afterlife. His body is recovered by Ben's owner and buried by his former owner, Iguchi. In the afterlife, he reunites with other fallen Ohu Army members. Later, in "Ginga Densetsu Weed: Orion," he is revealed to have a nephew named Andy. John was born in Finland, though earlier sources inconsistently listed Tokyo as his birthplace.