Hero's of old.
The legends of all / most Humans tell of Civilizing Heroes, Angels, Gods, or even Demons and Monsters who were their civilizers and who taught them religion, law, agriculture, metallurgy and the alphabet. These are the Fallen Angels, the same all too human heroes who fell desperately in love with the beautiful native girls, the Daughters of Man (Gen. 6). These fallen gods were not Astronauts, nor Sprites, but Atlantian men who came as missionaries, or came for the adventure and exploration , or even sometimes there own selfish means ,from Atlantis. How else could they mate with human females and breed children?
(*note* biologically a atlantian is extremely simular to a human and come form the same base species , the variant of Atlantians comes form excessive Magical energy effecting there bodies , much like some radiations can have adverse affects on us today , the Mutations over the generations caused something much stronger to develop which has more of a natural amplitude for those energies, The Atlantians are classifed as Homo-Atlantius)
The mysterious "Sons of God" of Gen.6 are precisely the same ones identified by Plato with the Atlanteans. Their sin with the Daughters of Men and, more probably, the rejection and enslavenment of their hybrid offspring led to the Flood. This is indeed the mysterious Original Sin that resulted in the destruction of Paradise (Atlantis) and the Fall of Man. This sin is the one ritually "washed" by the Baptism, itself an allegory of the Flood, as St. Jerome and other Church Patriarchs explicitly acknowledge. And this adverse cultural experience to the old more barbaric Atlantian clans caused them to develope laws againt breeding with humans and most out of species lifeforms , though it can happen today but there is still a great learners about going about the process.
Plato quotes precisely this cause for the destruction of Atlantis by God (Zeus) in his (unfinished) dialogue on Atlantis, the Critias. And the same story, in allegorized form, is also told by Homer concerning the Phaeacian "Sons of God". It also figures in the Celtic myths concerning Mererid, the sinful daughter of King Gradlon, whose scabrous conduct led to the sinking of the land of Ys. So, in the Americas (Bochica, etc.) and elsewhere.
If we read the Bible attentively, we note that it also speaks of two creations, exactly as Plato also tells of two different Atlantises (cf. Gen. 1 and 2). Moreover, the Bible also tells of two destructions of the world by the Deluge. These two different narratives are quaintly embroidered on each other in Gen. 6, and comprise the Elohist and the Jahvist accounts of the Flood, which relate two visibly different events