Masamune Date leads the Date family, having lost his right eye to childhood smallpox. This injury initially fostered withdrawal and pessimism but evolved into an intense fixation on eyepatches, driving him to collect absurdly elaborate designs. His retainers, Katakura Kagetsuna and Date Shigezane, routinely endure his compulsive showcasing of new acquisitions.

Eccentric and flamboyant, Date neglects governance and strategy for delusional fantasies where he reinvents himself as a superhero or grandiose figure. He insists his eye was lost battling a cuckoo bird—a fabrication exasperating his retainers. His behavior often regresses to childlike stubbornness, inviting comparisons to a middle schooler's maturity.

Kagetsuna and Shigezane critically manage his impulsiveness, regretting their influence during his upbringing as a potential catalyst for his eccentricity. Despite their efforts to instill rationality, Date fixates on eyepatch displays and imaginative scenarios. Critiques of his eyepatches or appearance trigger severe depression, comically reverting his face to a historically accurate, less attractive visage.

Inspired by the historical "One-Eyed Dragon" known for tactical brilliance and cultural patronage, this version comically inverts the legacy. His crescent-moon helmet receives obsessive attention, mirroring his eyepatch fascination. His leadership showcases incompetence rather than strategic genius.

The character remains consistent across all media—*Tono to Issho: Ippunkan Gekijōu* (2010), *Tono to Issho: Gantai no Yabō* (2011), and the original OVA (2010)—with no development. He sports blue hair and golden eyes, though depressive episodes distort his features comically.