Blue Skinned People
Blue skinned humans information is related to Agharta (Sometimes written elsewhere as Agartha and occasionally written as Agartta, Agharti, Agarta or Agarttha). In Contact Report 039 published in 1975, Billy reminds Ptaah that while he was in India and in the Himalayas for a long time, he encountered the blue human beings. It's clarified in a forum answer that Billy never spoke with the blue-skinned people, but he knows that they are not a part of The Mission. Since he did not speak with them, he doesn’t know what they are doing or not doing.
Ptaah in Contact Report 039 from line 211 says: "this much may be said, that in the vicinity of Shigatse and Shampulla is the underground realm of Agharta, the capital and centre of distant descendants of extraterrestrials on Earth. This is the center of the actual secrets that hold a gigantic power in themselves. This city is controlled by the race of the Sons of the Sun. But unfortunately, a tendency toward earthly world domination also prevails with this race, just like with certain earthly religions and secret societies. I may not explain anything else about it openly."
It is related to Atlantis.