Peter Ferguson, whose name appears in some English materials as Fargason or Fargusen, is a major supporting character in the Gonzo-produced Hellsing anime. Before joining the Hellsing Organisation, he served as a captain in the British Army, making him a career soldier with considerable combat and command experience. He is also a veteran and a father, and he has aged into an older man distinguished by white hair, red eyes, and a deep voice. His military background and maturity make him a stabilising presence within an organisation otherwise dominated by the monstrous, the supernatural, and the fanatical.

Within the Hellsing Organisation, Ferguson holds the position of commander of its entire paramilitary force. In practical terms, this makes him the highest-ranking human soldier in the organisation's military structure, with Sir Integra Hellsing as his only true superior. Although Integra holds ultimate authority, he also listens to Alucard, the organisation's powerful vampire exterminator, reflecting the unusual chain of command that defines Hellsing. His duties involve coordinating the organisation's soldiers, giving specific operational instructions to the leaders of individual teams, and ensuring that missions are carried out effectively. Despite his command role, he is not the type of officer who remains safely behind the lines; when the situation demands it, he is willing to stand on the frontlines alongside his troops.

In terms of personality, Ferguson is portrayed as an extremely loyal and dependable soldier. He carries himself with the discipline and pragmatism of a career officer, and he is committed to getting the job done no matter the circumstances. He is also a compassionate leader, particularly toward the soldiers under his command. This combination of toughness and care is most visible in his relationship with Seras Victoria. After Seras is turned into a vampire and joins the organisation, Ferguson becomes her first tactical trainer. He works closely with her to turn her into an effective soldier and to draw out her natural talents, guiding her through a difficult transition that is both physical and psychological. His mentorship helps Seras adapt to her new existence and find her place within Hellsing.

Ferguson's motivations are rooted in duty and service. He is a soldier by profession and by temperament, and his loyalty to Integra and the Hellsing Organisation is presented as genuine and unwavering. His recruitment work also speaks to his practical judgment: he personally found and brought together the mercenary group known as the Atheists and Heathens, which was hired by Integra to serve the organisation. This shows that he is not merely a battlefield commander but also someone capable of sourcing, evaluating, and assembling the unconventional personnel that Hellsing requires.

In the broader story, Ferguson functions as the human military backbone of the organisation. While Alucard handles the most extreme supernatural threats, Ferguson ensures that the ordinary soldiers are organised, trained, and led during operations. He has no supernatural abilities of his own; his strengths lie in his veteran knowledge, tactical command, marksmanship, and willingness to fight when needed. His character does not undergo a dramatic transformation over the course of the anime. Instead, his development is more understated, seen through his steady guidance of Seras and his constant, reliable service to Integra during the escalating conflicts the organisation faces. He represents the mortal element of Hellsing, a professional soldier who remains effective and honourable even in a world of vampires and monsters.