Corkus begins his story as the leader of a small band of thieves before encountering the Band of the Hawk. He challenges Griffith and is defeated, after which he chooses to join the group, hoping to achieve wealth, fame, and women through his martial skill. Within the band, he commands his own unit, which gains a reputation for always returning from battle alive. Physically, he is depicted as a man with brown eyes and smooth black hair that reaches the base of his neck.

In terms of personality, Corkus is defined by his outspoken and unfiltered nature. He is cynical, sarcastic, and boasts a boisterous love for victory, alcohol, and women, often playing small jokes to entertain himself. Beneath this rough exterior, however, lies a solid code of ethics and an unbreakable loyalty to the Band of the Hawk. While he will complain about conditions before a fight, he is practical and gets the job done on the battlefield. A key nuance to his character is a hidden idealism. Fellow Hawk Judeau observes that Corkus once failed to achieve a personal dream of his own, a failure that leads him to revel in the glory and privileges gained under Griffith as a way to stave off these feelings of loss. This backstory informs his cynical, world-weary demeanor and his fierce devotion to Griffith’s dream.

Corkus’s most defining relationship is his antagonism toward the protagonist Guts. This hostility stems from the fact that Guts killed one of his subordinates before joining the band, and Corkus begins by barely tolerating his presence, constantly insulting him. His hatred is largely one-sided, as Guts does not majorly reciprocate it. When Guts decides to leave the band, Corkus expresses his disdain most fully, accusing Guts of being self-centered and acting as if he alone bears the world's burdens. Despite this, his feelings are more complicated. He secretly worries about and misses Guts after he leaves, but his pride prevents him from admitting it. In a rare moment of solidarity, Corkus also reassures Guts that Griffith’s later imprisonment was not his fault. While he is generally antagonistic toward Guts, he is notably nicer to the younger member Rickert, even if he still picks on him.

Throughout the Golden Age, Corkus plays the role of a grumpy realist, often voicing doubts about situations that others accept. He is fiercely loyal to Griffith and believes his commander is special and without equal. After Griffith is imprisoned and the band becomes a group of fugitives, Corkus becomes disillusioned but remains with the Hawks, believing the group has no meaning without its leader. He participates in the dangerous mission to rescue Griffith from his torture, despite his fading hopes.

Corkus meets his end during the Eclipse, the demonic ritual where the Band of the Hawk is sacrificed. As the Apostles slaughter his comrades, Corkus panics and flees, though he quickly realizes there is no escape. Driven to the brink of madness by the horror, he becomes delusional, trying to convince himself that everything is a nightmare. In this dazed state, he spots a naked woman and embraces her, trying to convince himself he is dreaming. The woman is in fact an Apostle in disguise, and it kills him immediately afterward. Guts later sees Corkus’s decapitated head within its jaws.

In terms of ability, Corkus is a competent fighter and leader, commanding enough respect to lead his own unit. However, compared to the more talented core members of the Hawks, he possesses no outstanding or exceptional martial skills to make him stand out.