Board Thread:Questions and Answers/@comment-32556318-20170712153049/@comment-36009152-20200115000009

Biological facts as we know know them may not be the same as that in the world of Seraph of the End, a work of fiction with vampires, resurrection and other fantasy related elements. The story has not shown all the facts as of yet but if Yu, or at least his memories is this black substance like entity that can be placed in, like the Yu that Sika Madu killed, then the one that Noya killed and transferred like that. Over the centuries it might be the case that it did come to form inside Yu's mother. All guesswork since information is being revealed gradually in the story.