Max Montana, often referred to by his military title the Major, is the main antagonist of Hellsing Ultimate. He is a former Sturmbannführer in the Waffen-SS during World War II, who was personally ordered by Adolf Hitler to lead a top-secret project aimed at perfecting an artificial vampirization process to create an army of Nazi vampires. Following the defeat of this force by Alucard and Walter in Poland near the end of the war, Montana and his surviving officers fled to South America. There, he spent the subsequent decades rebuilding his forces and planning a new campaign of destruction, becoming the supreme commander of the paramilitary terrorist organization known as Millennium.

Montana is defined by an all-consuming obsession with war for its own sake. He takes no interest in Nazi ideology, world domination, or any political goal; his sole desire is to experience endless conflict and slaughter. He is highly intelligent, a master strategist who develops complex, long-term plans that account for the personalities and likely actions of both his allies and enemies. He is also a charismatic and convincing orator, capable of inspiring fanatical loyalty in his soldiers, who eagerly follow him to their deaths. Despite his genial and polite demeanor at times, he is utterly ruthless, sadistic, and devoid of conventional morality, freely admitting that his organization has no purpose beyond wanton destruction.

Montana's central motivation is to wage an eternal war and to defeat Alucard, whom he considers his ultimate opponent. He rejects supernatural power in favor of his own human will. During the fall of Berlin, when he was gravely wounded by Soviet soldiers, he refused to drink blood and become a vampire, even though it would have allowed him to continue fighting indefinitely. Instead, he underwent extensive cybernetic modifications performed by his associate Doc, eventually becoming a cyborg. It is later revealed that his body for the entire series was that of a robotic shell, and he may have been long dead in a conventional sense. This choice underscores his core philosophy: he values the human capacity for free will and the pure, chaotic nature of war over the immortality and dependence of vampirism.

In the story, Montana is the driving force behind Millennium's invasion of London and the simultaneous attack on Washington, D.C. He orchestrates a devastating assault using three Zeppelins and a thousand Waffen-SS soldiers converted into vampires, resulting in the slaughter of millions of civilians and the near-destruction of the Hellsing organization. His rivalry with Alucard is the central conflict of the series, with Montana viewing the ancient vampire as a monster who lacks the true human spirit. His key relationship with his troops is one of absolute command; they revere him and are willing to die for his cause. He also has a history with Walter, the Hellsing butler, who was instrumental in defeating Montana's forces in Poland decades earlier.

Physically, Montana is short in stature, noticeably overweight, and possesses no combat prowess or marksmanship skills, a fact often played for dark comic effect. His notable abilities are entirely intellectual and strategic. He is a brilliant tactician and a master of psychological manipulation, able to weave intricate plots that unfold over half a century. His greatest weapon is his unshakable will and his terrifying charisma, which allow him to command the loyalty of fanatical followers and remain calm and defiant even in the face of certain defeat. Despite his fragile form and poor physical skills, he becomes one of the most destructive forces in the series, leaving London in ruins and forcing Alucard to unleash his full power, ultimately costing the vampire king a portion of his abilities.