Dantalion is an immortal great demon who forms a central part of the narrative, defined by his long existence and his complex relationship with a human companion. He is one of the major demonic figures in the story, whose actions and choices directly shape the conflicts that drive the plot forward. His background establishes him as a being of immense power and age, having lived through countless years alongside other supernatural entities like Marbas, another great demon who serves as a counterpart and rival. Unlike some of his kind who might shun humanity, Dantalion has specifically chosen a human partner, a decision born from a desire to alleviate the monotony of an eternal life. The initial purpose of this pact was a form of entertainment, a way to pass the endless years, but over time this bond grew into a unique and deeply significant relationship.

The personality of Dantalion is largely revealed through the nature of his choices and his interactions with the world. His decision to form a pact with a bloodthirsty maniac speaks to a certain pride, a detached curiosity, and perhaps a darker, more pragmatic aspect of his character. He does not seek out gentle or innocent company; instead, his chosen partner reflects a capacity for violence and a hunger for battle that Dantalion himself appears to share. This is evident in his actions, as he is shown to continue hungering long after combat and engaging in relentless attacks on powerful institutions like the headquarters of the Sword Cross Knights. His motivations are a blend of his own instinctual desires and his loyalty to his pact partner, driving him into direct and proud conflict with other demon-human pairs, most notably Marbas and his chosen human, Wisteria.

Dantalion’s role in the story is that of a key antagonist and a potent force of nature that the other protagonists must contend with. He is not simply a mindless monster but an active player in the struggle for London, participating in the final stages of a major battle to rid the city of demons. His presence elevates the stakes, as he represents the raw, predatory side of demonkind, driven by an endless appetite for conflict. This sets him in stark opposition to other characters who fight for more sentimental reasons such as pride, loved ones, or the protection of friends. The clash between these different motivations forms a significant part of the central conflict, with Dantalion and his partner serving as a mirror to Marbas and Wisteria, highlighting the different paths immortal beings and their human companions can take.

Regarding his development, the narrative suggests a significant evolution in his character. What began as a mere diversion or an attempt to stave off eternal boredom deepened into a substantial relationship that now dictates his actions and fuels his pride. He is not static; his connection to his human partner transforms him from a detached observer of time into an active participant in a specific, finite life, which in turn gives him a vested interest in the mortal conflicts of Britain. His notable abilities are inherent to his nature as a great demon, granting him immense physical power, resilience, and a terrifying proficiency in combat. He is a formidable fighter who does not shy away from battle but actively seeks it out, driven by an insatiable hunger that persists even after a fight has ended. The image of him with horns, a tail, and bull-like features, often dressed in a suit and tie, visually reinforces his nature as a powerful, civilized monster capable of both sophisticated thought and brutal violence.