ONE PIECE Gorosei and Their Yokai Inspirations

Ushi-oni appears chiefly on the coasts, in deep pools, and in the mountains of western Japan. It is among the fiercest and most numinous beings in the yokai tradition. Its body has no single form: some artists give it a bull's head on an oni's body, while others set the same head on the body of a spider. The Heian-period Pillow Book already names Ushi-oni among the things that inspire terror. Its most striking quality is a radical dual nature. In one guise, Ushi-oni is a cruel man-eater and bringer of disease that spreads poisonous breath without discrimination. In another, it leads a mikoshi procession and uses its tremendous force to drive away other evil spirits. Over time, a frightening presence in literature became part of regional worship and festival performance. Few yokai show so clearly how a destructive power could also be received as a guardian.

The Itsumade (以津真天) is a gigantic monster bird with a human-like face, a curved beak lined with saw-like teeth, a long serpentine body, and sharp sword-like spurs on its legs. Said to possess a wingspan of up to one *jō* six *shaku* (approximately 4.8 meters), it terrifies people by echoing its eerie cry of "Itsumade, itsumade" ("Until when? Until when?") from the night sky. The primary source of this yokai is an anecdote about an unnamed "monster bird" recorded in Volume 12, "The Matter of Hiroari Shooting the Monster Bird," of the pinnacle of war chronicles, the *Taiheiki* (established in the 14th century). According to the legend, in the autumn of the first year of the Kenmu era (1334), as an epidemic ravaged Heian-kyō (Kyoto) and claimed countless lives, this creature flew above the Shishinden (the Kyoto Imperial Palace) every night, letting out its ominous cry until it was brilliantly shot down by the master archer Oki no Jirōzaemon Hiroari. Crucially, in classical texts, this bird was consistently referred to only as a "monster bird" and lacked a specific proper name. It wasn't until the Edo period that the painter Toriyama Sekien included it in his *Konjaku Gazu Zoku Hyakki* (1779), applying the kanji "以津真天" (Itsumade) to its cry, that it crystallized as a distinct named yokai for the first time. In modern yokai encyclopedias, it is often explained that it "appears beside corpses left abandoned due to war or famine, crying out in protest, 'Until when (will you leave them exposed to the elements)?'" However, this direct connection to "corpses" is absent from medieval and early modern literature; it is a later interpretation added in modern times that logically reinterprets the *Taiheiki*'s backdrop of a rampant epidemic.

Houki is originally not a Japanese yokai, but a colossal and ferocious wild boar monster (or divine beast) recorded in ancient Chinese mythology and geographical texts such as the *Classic of Mountains and Seas* (Shanhaijing). Pronounced "Fengxi" in Chinese, it became established in Japan through its Sino-Japanese reading "Houki". According to legend, it is an impossibly massive boar completely covered in a hide as hard as armor. It was feared as a living disaster, using its overwhelming power to ravage farmlands and devour people. In Japan, it was introduced to the educated class via "tales of foreign lands" in Edo-period encyclopedias like the *Wakan Sansai Zue*, but it never developed into a folk belief (folk yokai) rooted in local regions. For a long time, it remained merely an "imported monster" confined to the pages of books. However, in modern times, its name has suddenly been thrust into the spotlight through pop culture media such as manga and anime.

Bakotsu is a *mukuro* (corpse) yokai said to be the animated skeletal remains of a horse that burned to death in a fire, having absorbed eerie spiritual energy after being denied a proper burial. It is famously depicted in the *Tosa Obake Zoshi* (Tosa Yokai Scroll), produced in Tosa Province (modern-day Kochi Prefecture) during the mid-to-late Edo period. It possesses a bizarre and uncanny appearance: a gigantic, fully skeletonized horse standing upright on two legs, draped in tattered, threadbare rags around its waist. Among the many yokai traditions across Japan, it is extremely rare for a “horse skeleton” to move autonomously. Rather than being a malevolent, vengeful spirit that actively attacks or curses humans, Bakotsu embodies the regret of livestock meeting an untimely end and the sorrow of “beasts of burden” cast aside the moment they outlive their usefulness. Though an apparition that startles travelers on old night roads, it serves as a cautionary tale emphasizing the importance of *chikusho kuyo* (memorial services for animals) and the ethical duty to respect living creatures to the very end. Thus, it strongly reflects the localized folk beliefs and views on life and death of the Shikoku region.

The Sandworm does not appear in any classical Japanese yokai picture scrolls or folktales; it is, so to speak, a "modern imported yokai." It is known as a giant worm monster that digs through the underground of deserts and sand dunes at breakneck speed, swallowing prey whole along with the sand using its massive, cylindrical mouth. Its direct origin is definitively traced to the Sandworms (Shai-Hulud) appearing in Frank Herbert's 1965 monumental sci-fi novel *Dune*. However, since the 1980s, its recognition exploded in Japan through fantasy RPGs like *Final Fantasy*. It has completely taken root among Japanese youth as a shared terrifying experience (a kind of modern folklore) as "the most terrifying monster that surely lurks in the harsh environment of a desert," making it an anomaly with an extremely unique history of reception.