Katakura Kojūrō is the chief strategist and most trusted retainer of Date Masamune in Sengoku Basara: End of Judgement. His role as a loyal subject is so profound that he is famously known as the Right Eye of the Dragon, a title that reflects his function as the冷静 and stabilizing counterpart to his lord’s more impulsive nature. His character draws inspiration from the historical figure Katakura Kagetsuna, a renowned samurai of the late Sengoku period celebrated for his wisdom and unwavering fidelity to the Date clan.

Kojūrō’s personality is defined by a disciplined and often stoic demeanor, which acts as a foil to the flashy and aggressive temperament of Masamune. He is calm, patient, and logical, refusing to take any action without a solid strategic backing. His manner of speech is direct and can be perceived as gruff, particularly towards those outside his immediate circle. However, this composed exterior is a carefully maintained persona. In his youth, Kojūrō was hot-headed and reckless, and the restraint he shows in the present is a conscious choice he made to allow Masamune to be the dynamic leader the clan needs. This inner intensity can resurface, particularly when Masamune is threatened, revealing a more aggressive and unrestrained side to his character.

His primary motivation is the fulfillment of Masamune’s ambition to unify the nation. Kojūrō lives in service to his master, a bond built on near-absolute trust. He is not a blind follower but an essential advisor, willing to directly confront or even incapacitate Masamune to prevent him from making self-destructive decisions. This loyalty is absolute; on one occasion, Kojūrō offered to commit seppuku as penance for failing to protect his lord from injury, demonstrating the depth of his dedication to the code of honor he lives by. In End of Judgement, his strategic mind is crucial as the Date clan navigates the tumultuous events following the death of Toyotomi Hideyoshi. He often tempers Masamune's reckless charges with pragmatic guidance, focusing on the long-term survival of their clan over immediate glory.

The core of Kojūrō’s character is his relationship with Masamune Date. While he is a mentor and protector, he is also a subordinate who has dedicated his entire being to his lord’s cause. He views Masamune as the future leader of Japan and is determined to bring that destiny to pass. Throughout the series, Kojūrō undergoes subtle but significant development, primarily centered on the concept of restraint versus release. While he is the voice of caution, the narrative often hints that he is a fearsome warrior who holds back his full power, a restraint that is part of his service to Masamune. His arc in the story involves moments of self-sacrifice and unwavering duty, such as orchestrating defenses against powerful threats like the Toyotomi forces and accepting personal risk to protect the Date clan’s interests, which solidifies his role not just as a retainer, but as a brotherly figure and a pillar of strength for Masamune.

In combat, Kojūrō is a highly skilled and strategic fighter. Unlike many characters who wield flashy or oversized weapons, he fights with a traditional daisho, a pair of matched katana and wakizashi. His swordsmanship is straightforward and powerful, relying on strength and precision rather than acrobatics. Despite its simplicity, his skill is immense, as he is fully capable of matching Masamune, who is considered one of the series' most formidable swordfighters. His elemental alignment is lightning, which manifests as an aura that enhances his attacks. He also employs specific techniques, such as Kasumi Dangetsu and Ugachi Tsuki, and can enter a heightened state known as Gokusatsu mode, which greatly amplifies his offensive capabilities at the cost of his defense. Beyond his martial prowess, his most valuable asset is his tactical genius. He is an extremely skilled strategist capable of analyzing and countering the plans of other military commanders, making him indispensable to the Date clan's campaigns and governance.