Flange is a significant supporting character in the fleet of the Gargantia, recognized as one of its primary ship owners and an executive with considerable influence over the community’s decisions. In terms of his appearance, Flange is depicted as an adult man with blonde hair and dark eyes. He is a conservative and pragmatic leader who ultimately shows a strong sense of responsibility for the well-being of the people under his protection.

Initially, Flange's personality is defined by a cautious and traditional mindset. As a major ship owner, he holds a seat among the fleet's leadership and was initially opposed to allowing the mecha pilot Ledo and his artificial intelligence unit Chamber to remain with the Gargantia. He viewed the outsider and his powerful weapon as a potential threat to the fleet's established way of life. However, his motivations are not rooted in selfishness or greed. Flange is later driven by a desire to improve the lives of the fleet's citizens by salvaging the relics of past human civilization from the ocean floor. This goal leads him to form a crucial alliance with Pinion, an ambitious and reckless engineer who shares a desire to explore the dangerous territories of the whale squid, which are sacred creatures to the people of Gargantia.

Flange's role in the story becomes most prominent following the death of the Gargantia's beloved commander, Fairlock. In the ensuing power vacuum and societal tension, Flange decides to lead a faction of ships to break away from the main Gargantia fleet. This decision places him at the center of a major conflict, as his group seeks to harness Ledo's combat abilities to defeat the whale squids and claim the valuable technology hidden in their nests. Despite being a powerful ship owner, Flange finds his authority challenged by the unpredictable and dangerous obsession of Pinion, who becomes increasingly fixated on the salvaged technology.

As the situation escalates, Flange's fleet encounters the Kugel fleet, a militaristic group led by a mecha similar to Chamber. Initially reluctant, Flange is eventually forced to cooperate with this new, more authoritarian regime. It is during this arc that his character demonstrates significant development. Upon witnessing the oppressive and inhumane nature of the Kugel fleet, which sacrifices the weak for its own survival, Flange makes a decisive stand. He chooses to rebel against this force, risking his own position and safety. During the ensuing battle, he prioritizes the evacuation of non-combatant residents, showing himself to be a true leader who values the lives of his people above all else. He ultimately leads his remaining fleet back to rejoin the main Gargantia.

Regarding his abilities, Flange does not possess any special combat skills or personal weapons. His primary contributions are his authority as a major fleet owner and his strategic decision-making as an executive. He has the power to influence the direction of the Gargantia's politics and to command a significant number of ships and crew. His key relationships include his partnership with Pinion, which is based on mutual benefit but becomes tense due to Pinion's recklessness; his loyalty to the late Commander Fairlock; and his respectful but cautious relationship with Ridget, another leader of the Gargantia. His notable abilities are those of leadership and governance, which he ultimately uses to protect his followers in a time of crisis.