Frankenstein’s Monster, called Frankenstein or Franken in the series, emerges as a Western yōkai rooted in Mary Shelley’s classic tale, its appearance mirroring Boris Karloff’s iconic 1931 film depiction. Serving under Backbeard in the Western Yōkai Army, it debuts within *The Great Yōkai War* saga across manga and anime mediums. A hulking figure marked by raw power and resilience, the creature’s intellectual shortcomings frequently offset its combat prowess. Occasionally, it taps into a latent ability to escalate its strength to rival adversaries—a phenomenon peers deem unnervingly primal for a yōkai. Notable idiosyncrasies, such as an aversion to insects and a penchant for milk, punctuate its characterization in cinematic portrayals. Twelve years before the fifth anime’s timeline, the monster fought in the inaugural Great Yōkai War, distinguishing itself among the rare Western entities active in that clash. It harbors a longstanding feud with Konaki-Jijii, a native yōkai, and later allies with Dracula II, Wolfman, and Witch to storm Jigoku (Hell), thwarting the Kitarō lineage’s advance. The *Ao no Koku* novel frames the creature as Backbeard’s lieutenant and a warrior in the Kikaiga Island skirmishes during the Great Yōkai War. Its narrative role oscillates between active antagonist and metaphor for Western cultural imposition, echoing post-war Japan’s identity tensions. The monster’s design and allegorical function parallel Cold War-era fears, its coalition symbolizing external threats within the series’ symbolic struggles. Consistently portrayed as a brawny, loyal enforcer for Backbeard, the creature’s dim wit renders it prone to exploitation, exemplified by its petrification under Gorgon’s gaze. Its enduring presence cements it as a recurring foe in the clash between Eastern and Western yōkai factions, anchoring its legacy within the saga’s mythic conflicts.