"Last Round Arthurs" is a manga series that blends elements of fantasy, action, and mythology, centered around a modern-day battle for the legendary sword Excalibur. The story is set in a world where King Arthur's legacy lives on through reincarnations of the Knights of the Round Table, who are destined to fight for control of Excalibur. The protagonist, Rintarou Magami, is a high school student who discovers he is the reincarnation of Sir Lancelot. Rintarou is drawn into a conflict involving other reincarnated knights, each vying to claim Excalibur and fulfill their own ambitions.

The narrative unfolds as Rintarou encounters Luna Artur, a mysterious girl who claims to be the reincarnation of King Arthur. Luna seeks to gather the knights to prevent Excalibur from falling into the wrong hands, as its power could bring catastrophic consequences if misused. The story explores the dynamics between the reincarnated knights, each with their own motivations and interpretations of Arthurian ideals. Key characters include Felicia Lionett, the reincarnation of Sir Gawain, who initially opposes Rintarou but later becomes an ally, and Shinra Kuroshiba, the reincarnation of Sir Mordred, who harbors a deep grudge against Arthur and seeks to destroy Excalibur.

As the plot progresses, the knights engage in intense battles, both physical and ideological, as they grapple with their past lives and the responsibilities tied to their reincarnations. The manga delves into themes of loyalty, betrayal, and the weight of legacy, as the characters navigate their roles in the modern world while being bound by the ancient legends of Camelot. The story builds toward a climactic confrontation over Excalibur, with the fate of the world hanging in the balance. The series combines fast-paced action with character-driven drama, offering a fresh take on Arthurian mythology within a contemporary setting.