"By the Sword" is a manga series that blends elements of action, drama, and historical fiction. The narrative centers on a young swordsman named Rintaro, who becomes entangled in a web of political intrigue and personal vendettas in a feudal-inspired world. Rintaro, an orphan raised by a master swordsman, is driven by a desire to uncover the truth behind his mentor's mysterious death. His journey leads him to cross paths with powerful factions vying for control of the land, including corrupt nobles, rival samurai clans, and shadowy organizations.

The story unfolds as Rintaro hones his swordsmanship while navigating a morally complex landscape. Along the way, he encounters a diverse cast of characters, each with their own motivations and secrets. Among them is Ayame, a skilled warrior with a tragic past, who becomes both an ally and a source of emotional conflict for Rintaro. Another key figure is Lord Kuroda, a cunning nobleman whose ambitions threaten to destabilize the region. As Rintaro delves deeper into the conspiracy surrounding his mentor's death, he uncovers ties to a legendary sword said to grant its wielder unparalleled power.

The plot is driven by a series of intense duels, strategic battles, and shifting alliances, with Rintaro often forced to question his own principles and loyalties. Themes of honor, revenge, and the cost of power are explored as the story progresses, with the characters' choices having far-reaching consequences. The manga balances its action-packed sequences with quieter moments of introspection, highlighting the personal struggles and growth of its protagonists. The narrative builds toward a climactic confrontation that ties together the various threads of the story, culminating in a resolution that leaves room for reflection on the nature of justice and sacrifice.