Heiroku is one of Japanese yokai (ghosts, spirits and monsters) that was portrayed in Sekien TORIYAMA's yokai art collection book: "Hyakki Tsurezure Bukuro" (The Bag of One Hundred Random Demons; the term 'hyakki' in its title is a pun on the usual hyakki, replacing the character for demon which is written as "鬼" in Japanese with a character for vessel written as "器," and sure enough, most of the yokais shown in this book are tsukumogami [a type of Japanese spirits that originate in items or artifacts that have reached their 100th birthday and become alive]). It is portrayed as a strange yokai brandishing a gohei (wooden Shinto ritual wand with a pair of white zigzag paper streamers), and it is regarded as a tsukumogami.
Since Sekien did not leave any description on the Heiroku in the book, details are unknown.
According to some researchers including Shigeru MIZUKI, yokai cartoonist, 'Heiroku is a yokai which brandishes a Kotobure paper (a piece of paper with a handwritten message), claiming it an oracle, and spreads false rumors to confuse people.'
Kenji MURAKAMI, a yokai investigator, has insisted that the Heiroku should be modeled on a red ogre-like yokai that holds the gohei which is depicted in "Hyakki yagyo emaki" (a Night Parade of One Hundred Demons' picture scroll) of the Muromachi period.