Hidden detail of Seiko's introduction in Dandadan teases the truth of her existence

Yukinobu Tatsu's Dandadan features few characters who match the mysterious aura of Momo's grandmother, Seiko, who stands out as eccentric yet powerful. While fans have long speculated about her mysterious background and extraordinary abilities, one subtle detail in the manga's character introductions has sparked a compelling theory: Grandma Seiko may be immortal.

The fact that Seiko's introduction does not show a family name creates an intriguing hint about her actual identity and ancient roots. Did Dandadan's most powerful spiritual warrior become immortal by eating mythical mermaid flesh hundreds of years ago?

Disclaimer: This article is a speculative theory and reflects the writer's opinion.

---

Seiko’s mysterious origins in Dandadan: A possible link to Japan’s Imperial Lineage or a Pre-Meiji Era survivor

Grandma Seiko Immortal?! The Mermaid Flesh Theory byu/SuzumesScroll inDandadan

In Japanese culture, the absence of a family name typically indicates one of two possibilities: A Japanese individual without a surname either belongs to the Imperial family or their existence dates back to the establishment of surnames, which occurred during the Meiji era.

The former explanation gains credibility when considering Seiko's unmistakably common background. Seiko’s life would have to span several centuries if she lived through the period before Japanese people adopted surnames. Seiko's exceptional spiritual wisdom, combined with her combat skills, reinforces this theory.

Seiko's deep understanding of supernatural creatures and mystical events throughout the series demonstrates centuries of lived experience rather than expertise obtained within one lifetime. Her fearless approach to battling lethal yokai reveals her long history of seeing many supernatural threats emerge and disappear.

---

Seiko’s Sukajan and the immortality myth in Dandadan

The theory receives further support by analyzing Seiko's sukajan jacket, which displays a prominent Amabie pattern. The Japanese yokai Amabie takes on the form of a mermaid while serving traditional roles by foretelling either great harvests or impending epidemics.

The appearance of this iconography represents a deliberate homage to the origin of her extended lifespan. According to Japanese folklore, consuming ningyo (人魚), or mermaid flesh, gives immortality to those who eat it.

The tale of Yao Bikuni stands as the most famous version of the myth, where a woman consumed mermaid flesh by accident and lived for 800 years without showing signs of aging. Seiko stands out as a parallel since she is an ancient woman possessing exceptional abilities who potentially ceased to age internally many centuries prior.

---

A global mythological connection to mermaid lore and eternal life in Dandadan

This folklore isn't unique to Japan. Different cultures worldwide have their own versions of mermaid myths, and distinct attributes are given to mermaid flesh.

Certain European cultural beliefs held that eating parts of mythical ocean creatures would bestow powerful healing abilities or extended lifespans. The "immortal peach" from Chinese mythology demonstrates shared thematic elements with global myths about consuming magical objects to gain eternal life.

The validity of this theory would transform our understanding of Seiko's role in the series into something intriguing.

Her role as Momo's and Okarun's mentor becomes more meaningful because she represents more than just an experienced grandmother; she might be a centuries-old guardian who has seen multiple supernatural cycles. Seiko's nonchalant response to peril may come from her vast experience with many such encounters throughout her existence.

---

Conclusion

Seiko as seen in the anime (Image via Science SARU)

Yukinobu Tatsu masterfully intertwines deep insights within small details throughout his work. The mystery surrounding Seiko's possible immortality integrates seamlessly into the anime's unique combination of horror and comedic elements with surprising depth.

Throughout the series, Grandma Seiko proves to be a captivating figure, whether her rumored immortality holds true or not. She presents herself as an ordinary old woman while maintaining extraordinary secrets that stretch back through time.

---