Mighty Atom

In 17th century Japan, a cluster of nano-bots took the form of Mighty Atom, who was known to be a fantasy for children. (COMIC: The Road to Hell)

Behind the scenes
While not named within the story, the vision of the character, and later, the form a cluster of nano-bots took, was obviously meant to be Mighty Atom, known as Astro Boy to Western audiences.