And he's using that knowledge to his advantage... better disguises, changing his MO, carefully executing his abductions.
No prince with a sinister reputation would have had the chance of executing the series of crimes which placed him on the throne.
All this points to a temporary occupation by a race at a far higher stage of culture than any known Australians, who were certainly never capable of executing even the crude works of art described.
Then who was executing him, killing him, depriving him of life--him, Pierre, with all his memories, aspirations, hopes, and thoughts?
No one else would be capable of executing the dramatic capture of my nemesis and the lovely child as well.