Corkus is a secondary character who serves as a high-ranking officer within the Band of the Hawk, commanding his own unit. Before joining the mercenary group, he led a small band of bandits. After a failed challenge against Griffith, he recognized the young leader's potential and chose to follow him, hoping to achieve wealth, fame, and women through his sword. Later, as part of a plan to rob Guts, he was defeated, an event that ultimately contributed to Guts joining the Band of the Hawk and which also caused Corkus to harbor a deep, lasting resentment towards the new recruit.

In terms of personality, Corkus is defined by his cynical, sarcastic, and brutally honest nature. He rarely censors his opinions, often voicing contrary views with a sharp tongue, and is known for being opportunistic and brash. Despite his rough exterior and tendency towards petty jokes, he holds a solid code of ethics and an unbreakable bond of loyalty to the Band of the Hawk. He is a practical realist who mistrusts lofty ideals and dreams, which paradoxically is why he sees Griffith as someone truly special for achieving the impossible. His hostility towards Guts is a defining trait, initially stemming from Guts killing two of his subordinates. He constantly insults Guts and picks fights, yet this animosity is complex; it masks an underlying worry and even a resemblance to Guts' own earlier, ambition-driven nature. Others in the band recognize that Corkus is too proud to admit he misses Guts when he is gone.

Corkus's role in the story is primarily as a senior commander of the Hawks and as a persistent, grating rival to Guts. He voices the pragmatic, grounded perspective within the group, often serving as a foil to Guts's solitary path and Griffith's grand ambition. His motivations are simple and grounded: he seeks a good life of booze, women, and victory within the secure structure of Griffith's dream, having long since abandoned any grand personal aspirations of his own. He commands a unit famed for always returning from battle alive, indicating his competence and the respect he commands from his men despite his unpleasant demeanor.

Corkus has key relationships with several characters. His most significant and antagonistic relationship is with Guts, whom he criticizes relentlessly but comes to acknowledge as a fellow Hawk after notable victories. He has a deep, almost worshipful admiration for Griffith, seeing him as the one person capable of transcending the realistic limitations that bind others. He is notably kinder to the young recruit Rickert, often picking on him in a more good-natured way.

Corkus undergoes a subtle but significant development as the story progresses. His initial boisterous confidence gives way to disillusionment after Guts leaves the band and Griffith is imprisoned, leading him to despair over the future of the Hawks. His hostility towards Guts is also reinterpreted; it is suggested that he sees his own failed, forgotten dream reflected in Guts, and his anger is as much about his own resignation as it is about Guts's actions. In terms of abilities, Corkus is a skilled and experienced warrior who wields a sword and leads his men effectively in combat, with a reputation for survival. However, he is not portrayed as being in the same league as fighters like Guts or Griffith.

During the Eclipse, the demonic ceremony where the Band of the Hawk is sacrificed, Corkus is overwhelmed by terror. He initially tries to run from the Apostles but quickly realizes there is no escape. Falling into a state of shock and denial, he attempts to convince himself the entire horrific event is a dream. In his delusional state, he sees the body of a nude woman and embraces it, only to realize too late that it is bait used by a female Apostle. This Apostle kills him, and Guts later finds his severed head in its jaws.