Which of the french dignitaries is the principal vilan in the novel the 3 musketeers?

The principal villain in Alexandre Dumas's novel "The Three Musketeers" is Cardinal Richelieu. As the Chief Minister to King Louis XIII, he embodies political intrigue and manipulation, often working against the protagonists, Athos, Porthos, and Aramis. His ambitions and schemes drive much of the conflict in the story, positioning him as a formidable adversary to the musketeers.