After around a dozen children perished in a temple, whose residents were kids abandoned by their parents or orphaned by war, their spirits materialized into a Huge Fetus. The inhuman creature remained around the area, haunting the nearby creek and the temple itself. By chance, the Huge Fetus happened upon Hyakkimaru and Dororo, stalking the pair as they traveled around the area. The two ended up being invited to a nearby home where they learned that the temple had burned to the ground from a chance bolt of lightning. What they didn't realize was that the children were already dead before the fire started, consumed by the offspring of a demon and a human who were the ones to invite Hyakkimaru and Dororo to stay with them. As the truth is revealed, the Huge Fetus joins in the final attack against them. Releasing its spirits that drag the monster whose offspring had killed it within range of Hyakkimaru's blade, the Huge Fetus aids in revenging its death and appears briefly in a human form before vanishing forever.