User blog comment:IamJakuhoRaikoben/Chapter 508: Pleasure and Agony, Review./@comment-5303512-20161031161120/@comment-23853100-20161103021959

And hence we now know why he's so self-centered. He truly believes he's done everything on his own throughout his life.

His parents never gave birth to him, CNBA gave birth to himself. He was never under the care of his parents even as a baby, he took care of himself. CNBA3 never bought food or clothes before, he cook and sew them himself. CNBA3 never studied under a teacher before, he learnt everything on his own.

Everything is done on his own, no one else have assisted him along the way at all. This also explains why he's so oblivious to the real world.