Answering the First Progenitor's question, the 'Last' in question, who had become a Cosmic Being far earlier than they should have, thereby making themselves an even more tempting target in the eyes of Conceptual powers, and who had indirectly caused Lostvayne to create cracks in Balance's spell, which would eventually lead to more individuals from the Previous Era (including the First Progenitor) remembering the existence of the "Forgotten Fifth"—was currently busy transplanting the core of a not-so-random realm in a random galaxy, within one of the countless trillions of universes in the First Multiverse.
He had removed the Seed Engine and replaced it with the Spatial Law Crystal, and now, he sat there, waiting to see how this change would unfold.
While he waited, casually chatting with Lostvayne about random things, Celestia awoke, immediately sensing the change in Arthur's existence and ending up just as dumbfounded as Arthur himself had been.
