Demon Child

The Demon Child takes the shape of a deformed fetus with a reddened left eye. Born tiny, it balloons within moments to the size of an infant several months old. It is hairless, its infantile face marred by a growth on the forehead that hides the right eye. Lacking proper hands, its limbs taper into fingerless tendrils that force it to drag itself along on its belly, while a short tail trails behind.

Rarely uttering a word, the child still behaves with an awareness beyond its roughly two years of age. The Skull Knight explains that although it embraced an evil nature, it holds onto a kinship with its parents. True to that, it trails Guts across his years as the Black Swordsman without real hostility, once spurring him to avenge Vargas, and it repeatedly shields its mother. Its devotion runs so deep that it drains its own life force to keep her safe, and it can drive spirits away and cast hallucinations to protect her.

The child was conceived after a newly returned Guts lay with Casca. During the Eclipse, Griffith was reborn as the God Hand's Femto and violated Casca before a helpless Guts. Once the Skull Knight rescued the pair, Casca gave premature birth to the misshapen thing, which swelled swiftly to infant size. Guts moved to destroy it, but Casca held him back, and the Skull Knight revealed the child was his own, corrupted by Griffith. It faded away as the sun climbed.

Through Guts' vengeful wanderings the child followed after him, surfacing even in his rare moments of rest. In the Conviction Arc it warned him of Casca's peril, sometimes by wearing her face, and it took to guarding her directly at Albion, driving lingering spirits out of the bodies they had seized. As the Incarnation Ceremony neared, it spent nearly all its strength protecting Casca from the possessed blood of the dead and the flames of a transformed Mozgus.

Near death, the child was gathered up by the apostle called the Egg of the Perfect World, who swallowed it so that neither would die alone. Inside that shell, as the ceremony ran its course, the child matured into a human infant and then into the vessel for Griffith's returning essence. Even fused into Griffith's new body, a faint trace of its urge to protect Casca lingered on, surfacing again at the Hill of Swords.