I have spent years studying and teaching Japanese anime, exploring how its narratives intertwine with cultural, philosophical and religious traditions. One of the most compelling aspects of Japanese anime is its ability to merge thrilling action with deep spiritual and ethical questions.
“Demon Slayer: Mugen Train,” which shattered Japanese box-office records for earnings and ended up as 2020’s highest-grossing film in the world, is a prime example of how anime engages with these profound themes. With “Demon Slayer” continuing its global success, it is an opportune time to examine how it intertwines Buddhist, Shinto and samurai traditions into a narrative of heroism, impermanence and moral struggle.
Spiritual themes in anime
Anime often explores spiritual and philosophical questions by drawing on Japan’s religious traditions to examine themes of fate, self-sacrifice and the struggle between desire and duty.
Hayao Miyazaki’s “Princess Mononoke,” for example, follows Prince Ashitaka, who is cursed by a demon and must journey to find a cure. His quest leads him into a conflict between the industrialized Irontown, which seeks to expand by clearing forests, and the spirits of the natural world, including the Deer God, a divine being that governs life and death.
The film reflects Shinto principles by portraying nature as sacred and inhabited by “kami,” or spiritual beings. It emphasizes harmony between humans and the environment and the consequences of disrupting this balance.
Scholar Melissa Croteau, in her book “Transcendence and Spirituality in Japanese Cinema,” notes how Miyazaki’s films use nature spirits to critique modernity’s detachment from the sacredness of the environment.
A still from ‘Spirited Away’ in which 10-year-old Chihiro must learn to navigate an unseen world. (GoodFon.com, CC BY-NC)
Similarly, his 2001 animated film “Spirited Away” reflects animist ideas in Japanese culture, where spirits are believed to inhabit natural elements and even everyday objects. Set in a mysterious Japanese bathhouse filled with “kami,” 10-year-old Chihiro, once shy and afraid of change, learns to navigate this hidden world and transforms along the way.
A key moment in the film is the arrival of a polluted river spirit, which appears as a filthy, sludge-covered creature but is revealed to be a once-pristine river god, burdened by human waste. This scene embodies the animist belief that natural entities have their own spirit and must be respected. It also reinforces an environmental message: When nature is polluted or mistreated, it loses its vitality, but with care and reverence it can be restored.
“Neon Genesis Evangelion,” a landmark Japanese anime television series that aired from 1995 to 1996, engages with deep philosophical ideas, particularly existentialist questions of identity and purpose. Set in a postapocalyptic world, the series follows 14-year-old Shinji Ikari, who is recruited to pilot a giant biomechanical weapon called an evangelion to defend humanity against mysterious beings known as Angels.
As Shinji and his fellow pilots struggle with their roles, the series explores themes of isolation, self-worth and the challenges of forming close, meaningful relationships. It draws from both Buddhist and Gnostic thought, which emphasize a focus on inner spiritual knowledge and the belief that clinging too tightly to the material world causes suffering. Evangelion portrays suffering as arising from attachment and the inability to form meaningful relationships.
Rengoku: The embodiment of selfless heroism
What sets “Mugen Train” apart is its focus on the internal conflicts of its characters, symbolized by their battles with demons. These demons represent human suffering and attachment, themes deeply influenced by Buddhist thought. At the heart of the film is Kyojuro Rengoku, a demon slayer who embodies unwavering selflessness and honour.
Rengoku’s fire-based fighting style is deeply symbolic. In Japanese culture, fire represents both destruction and renewal. The Kurama Fire Festival, held annually on Oct. 22 in Kyoto, is a Shinto ritual where large torches are carried through the streets to ward off evil and purify the land.
Similarly, Buddhist goma fire ceremonies involve priests burning wooden sticks in sacred flames to symbolize the eradication of ignorance and desire. Rengoku’s own techniques reflect this duality: His flames cleanse the world of evil while signifying his unwavering spirit.
Bushido, the samurai code of honour, underpins Rengoku’s character. Rooted in Confucian ethics, Zen Buddhism and Shinto beliefs, this code emphasizes loyalty, self-sacrifice and duty to protect others. His mother’s teaching – “The strong must protect the weak” – guides his every action, reflecting the Confucian value of filial piety and the moral obligation to serve society.
Bushido’s connection to Zen Buddhism, with its focus on discipline and acceptance of impermanence, further shapes Rengoku’s unwavering resolve, while its Shinto influences reinforce his role as a guardian upholding a sacred duty.
Even approaching death, Rengoku remains steadfast, accepting impermanence, or “mujō,” a fundamental Buddhist principle that sees beauty in life’s transience. His sacrifice teaches that true strength lies in selflessness and moral integrity.
Akaza: A manifestation of attachment and suffering
Opposing Rengoku is Akaza, a demon who embodies the destructive consequences of clinging to power and immortality. Once human, Akaza became a demon in his obsession with strength, unable to accept the impermanence of life.
His refusal to acknowledge death aligns with Buddhist teachings that suffering arises from attachment and desire. Scholars such as Jacqueline Stone have explored how Buddhist texts portray clinging to existence as a fundamental source of suffering, a theme vividly reflected in Akaza’s character.
Visual elements reinforce Akaza’s symbolism. His body is covered in tattoos reminiscent of “irezumi,” traditional Japanese body art historically associated with crime and hardship. In Edo-period Japan, tattoos were often used to mark criminals, branding them as outcasts from society. Even today, irezumi remains stigmatized in many parts of Japan, with some public bathhouses, gyms and swimming pools barring individuals with visible tattoos due to their historical association with the yakuza. In contemporary anime, tattooed characters frequently symbolize a troubled past or inner turmoil, reinforcing Akaza’s role as a figure trapped by his own suffering and destructive path.
Akaza’s irezumi visually conveys his entrapment in cycles of suffering, reinforcing his contrast with Rengoku’s liberating flames.
A battle about human struggles
The battle between Rengoku and Akaza is more than a fight between good and evil; it is a clash between two worldviews – selflessness versus egoism, acceptance versus attachment. “Mugen Train” taps into universal human struggles, making its themes resonate far beyond Japan.
The film’s exploration of impermanence, moral duty and the pursuit of meaning contributes to anime’s broader legacy as a medium that entertains while provoking deep philosophical reflection.
As “Demon Slayer” continues to captivate audiences worldwide, evidenced by social media buzz around its new projects and the ongoing enthusiasm of fans, its success underscores anime’s ability to blend action with profound themes.
Whether through Rengoku’s selfless courage or Akaza’s tragic downfall, “Mugen Train” offers a timeless meditation on what it means to live with purpose and integrity.
Written by Ronald S. Green, Professor and Chair of the Department of Philosophy and Religious Studies, Coastal Carolina University
This article is republished from The Conversation under a Creative Commons license. Read the original article.
