In Yukinobu Tatsu’s Dandadan, few characters exude the enigmatic charm of Momo’s grandmother, Seiko. Her intriguing blend of eccentricity and formidable strength has led fans to ponder her hidden past and remarkable abilities. A particularly revealing aspect of her character introduction has ignited speculation: could Grandma Seiko actually be immortal?
The absence of a family name in her introduction hints at a deeper, more ancient identity. Is it possible that the strongest spiritual warrior in Dandadan achieved immortality by consuming the flesh of a mythical mermaid centuries ago?
Disclaimer: This article presents a speculative theory based on the author’s interpretations.
Exploring Seiko’s Origins: Links to Japan’s Imperial Lineage or a Survivor from the Pre-Meiji Era?
Grandma Seiko Immortal?! The Mermaid Flesh Theory by u/SuzumesScroll in Dandadan
In Japanese tradition, the absence of a surname often signifies that an individual belongs to the Imperial family or that they originate from the time before surnames were adopted during the Meiji era. The first possibility gains weight when we examine Seiko’s humble beginnings. If she existed before surnames became standard in Japan, it suggests she may have lived for several centuries.
Seiko’s impressive spiritual knowledge and combat prowess further support this possibility. Her rich understanding of supernatural beings throughout the narrative points to experiences accumulated over a lifetime spanning many eras rather than just a singular existence. Her bold approach to battling deadly yokai implies she has confronted numerous supernatural threats, honing her skills through extensive exposure.
Symbolism in Seiko’s Sukajan: Immortality and Myth in Dandadan
Seiko’s iconic sukajan jacket, adorned with an Amabie motif, adds another layer to the immortality theory. Amabie, a mermaid-like yokai in Japanese folklore, is traditionally seen as a harbinger of prosperity or calamity. This imagery may hint at the origins of her potentially extended lifespan.
According to folklore, consuming ningyo (人魚), or mermaid flesh, grants immortality. The tale of Yao Bikuni, who reportedly lived for 800 years after accidentally eating mermaid flesh, provides a compelling parallel to Seiko’s character, suggesting that she too may have ceased aging hundreds of years ago.
Global Mermaid Lore: Connecting Myths of Eternal Life in Dandadan
Mermaid mythology isn’t confined to Japan; cultures across the globe feature their own interpretations. In various European traditions, eating parts of these mythical sea creatures is said to confer extraordinary healing powers or prolonged life. Similarly, the “immortal peach”from Chinese legend echoes universal themes about consuming enchanted items for eternal life.
If this theory holds true, it would fundamentally reshape our understanding of Seiko’s character in Dandadan. Her mentorship role to Momo and Okarun transforms into a deeper narrative, suggesting she embodies the wisdom of a centuries-old guardian, having witnessed numerous supernatural phenomena throughout history. Her calm demeanor in the face of danger likely stems from extensive experience.
Conclusion

Yukinobu Tatsu seamlessly weaves profound insights into even the minutest details of his narrative. The enigma of Seiko’s possible immortality enriches the anime’s captivating blend of horror and comedy with unexpected depths.
Regardless of whether the legend of her immortality is true, Grandma Seiko remains an enthralling character, artfully balancing the guise of an ordinary elderly woman with extraordinary secrets that echo through the ages.