Yuji Sugiyama

Mankind can no longer reproduce because of gene manipulation aimed at making life longer. The clones ruling the bottomless underworld may have become fertile. Parton is selected to go on a mission through a subterranean labyrinth crawling with monsters to secure humanity's future.

1,042 years before JUNK HEAD, a robot named Robin escorts a human commander on a mission to the underground city of Carp Bar.